The present invention is directed to an apparatus for forming a multi-layer web formed from at least two polymeric film tubes in intimate contact with each other but not bonded to each other. The apparatus includes the use of a blown film extrusion die that extrudes two separate blown film polymeric tubes via two separate annular die lips. A fluid cooling system applies cooling fluid across a plurality of surfaces of the two blown film tubes. One of the die lips may be at a different height from the other die lip. The frost line of one blown film tube may be at a different height from the other blown film tube.

A catheter is made by coextruding first and second molten polymers, wherein the second molten polymer forms a flexible inner core and the first molten polymer forms exactly two bands on opposite sides of the inner core. The inner core is braided, and a third molten polymer extruded onto the braid to form a flexible jacket that encloses the braid, the bands and the inner core. The bands are more rigid than the inner core, and they provide preferential in-plane bending.

A catheter is made by coextruding first and second molten polymers, wherein the second molten polymer forms a flexible inner core and the first molten polymer forms exactly two bands on opposite sides of the inner core. The inner core is braided, and a third molten polymer extruded onto the braid to form a flexible jacket that encloses the braid, the bands and the inner core. The bands are more rigid than the inner core, and they provide preferential in-plane bending.

The present invention is directed to an apparatus for forming a multi-layer web formed from at least two polymeric film tubes in intimate contact with each other but not bonded to each other. The apparatus includes the use of a blown film extrusion die that extrudes two separate blown film polymeric tubes via two separate annular die lips. A fluid cooling system applies cooling fluid across a plurality of surfaces of the two blown film tubes. One of the die lips may be at a different height from the other die lip. The frost line of one blown film tube may be at a different height from the other blown film tube.

A reservoir made of a composite material includes a tubular element, two end fittings, each inserted into one end of the tubular element, and a circumferential layer that envelops the tubular element and the end fittings. The circumferential layer is made of resin-impregnated wound fibers. At least one segment of each end fitting has an outwardly tapering shape and the wall of the tubular element has a taper at each end, and thus at each end the wall is pressed against the segment surface having a tapering shape. The tubular element includes a plastic tube surrounded by a longitudinal layer essentially made of parallel fibers in a resin matrix, the parallel fibers being oriented along the longitudinal axis of the plastic tube. Finally, the circumferential layer is essentially made of fibers wound around the circumference of the tubular element and end fittings and parallel to each other.

Systems and methods can be used to produce fibers with external corrugations, internal corrugations, or both. These fibers can be used, for example, in hollow fiber membrane modules

Systems and methods can be used to produce fibers with external corrugations, internal corrugations, or both. These fibers can be used, for example, in hollow fiber membrane modules.

The present invention is directed to an apparatus for forming a multi-layer web formed from at least two polymeric film tubes in intimate contact with each other but not bonded to each other. The apparatus and method includes the use of a blown film extrusion die that extrudes two separate blown film polymeric tubes via two separate annular die lips. A fluid cooling system applies cooling fluid across a plurality of surfaces of the two blown film tubes. One of the die lips may be at a different height from the other die lip. The frost line of one blown film tube may be at a different height from the other blown film tube.

Provided is a hollow structure for fuel includes a polyamide resin layer (A), a polyamide resin layer (B) , and a polyamide resin layer (C) in this order from an outside. The polyamide resin layer (B) contains a polyolefin, the polyamide resin layer (C) contains a conductive substance, and an amount of an eluate in an eluate test using a pseudo fuel in the hollow structure for fuel is 25 g/m.sup.2 or less.

The method for forming from a round shaped cylinder to a square shaped cylinder or flat sheet which can be inserted in a square or rectangular shape metal pipe includes initiating turning of a heated mandrel, extruding heated polymer, wrapping while compressing a first layer of heated polymer or mesh, disposing a mesh or polymer layer over the cylinder encapsulating the cylinder on the turning mandrel while simultaneously laying a second layer of heated polymer over the turning mandrel and compressing the layer of heated polymer into the mesh layer and the mesh layer into the first layer of heated polymer simultaneously, and repeating the layering of the heated polymer and mesh layer until a desired wall thickness is reached.