Patent FR-2921860-A1 (FR)
Title: Manufacturing insulating tubular device, comprises forming insulating material with two-dimensional structure by superimposing number of layers, and forming insulating components that are axially precut in the material to form a preform
Inventor: LECLERCQ BERANGERE
IPC: B32B1/08
Filed: 2007-10-08
Abstract: The process for manufacturing an insulating tubular device (1) comprising a side wall having thickness (Ep) of 5-80 mm and an axial length (L) of 0.1-3 m, comprises forming an insulating material with two-dimensional structure with a thickness (E(M)) less than Ep, where E(M) is 0.5Ep by superimposing N number of layers (C i), where i is 2-N, and forming n iinsulating components that are axially precut in the material to form a preform (5), and heat treating the preform of tubular element at 1000[deg] C. The tubular insulating device comprises two layers C1 and C2 of the insulating material. The process for manufacturing an insulating tubular device (1) comprising a side wall having thickness (Ep) of 5-80 mm and an axial length (L) of 0.1-3 m, comprises forming an insulating material with two-dimensional structure with a thickness (E(M)) less than Ep, where E(M) is 0.5Ep by superimposing N number of layers (C i), where i is 2-N, and forming n iinsulating components that are axially precut in the material to form a preform (5), and heat treating the preform of tubular element at 1000[deg] C. The tubular insulating device comprises two layers C1 and C2 of the insulating material. The n iinsulating component forms the layer C1 after an edge to edge deposition. The preform is formed by assembling the components with the glue on an axial conformation and then polymerizing the glue for rigidifying the preform. The preform is heat treated so as to carbonize the glue. Components E iof each C 1layer is juxtaposed along a junction J i, and components E i+1 of the layer C i+1 is spaced apart from the components E iof the internal C ilayer so that the multiple junction areas J i+1 are spaced with respect to the multiple J ijunction areas. The J ijunction areas comprise J(A i) axial junction areas of axial length (L), and J(T i) cross junction areas of large axial length (L). The number of junctions J iforming the axial junctions J(A i) and the n iJ(A i) axial junctions are spaced at an angle of 360[deg] /n iwith respect to the axial direction. The number (n i) of insulating components remains the same for each layer C iof the insulating tubular device, where n typically varies with an average diameter (D). The insulating components form n 1insulating flat components and curved n 1insulating components before forming the preform. The components have a radius of curvature R iin a transverse plane perpendicular to the axial direction corresponding to the layer C 1. The preform is placed in a conformation mold comprising two reunited and closed half-shells to allow the preform to have predetermined and reproducible dimensions and geometrical sides. The insulating material is made of an expanded graphite having a thickness of 5-20 mm, and a layer having a density of 0.03-0.2 g/cm 3>and a layer having a density of 0.8-1.2 g/cm 3>. The thickness E rof a central low density layer is three times raised than a thickness E hof an outer high density layer. The glue comprises a thermosetting resin such as a phenolic resin, and is present in the form of powder or liquid form filled with an electro-conductive powder such as graphite or carbon black. The heat treatment comprises a complementary treatment of flash pyrolysis of methane to increase the rigidity of the insulating device, and a purification step in which the insulating device is heated to 2000[deg] C to remove any volatile component. The tubular insulating device forms a tube with constant section on axial length L, where the section is circular of diameter D, oval or polygonal. An independent claim is included for an insulating tubular device.