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AssigneeInstitut Francais du Petrole
InventorsJacques Jarrin, Emmanuel Vinciguerra, Gilles Ausias, Michel Vincent, Francois Dawans
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Fibre-reinforced tubes made of a thermoplastics material are manufactured using a method of extruding thermoplastics material in a drawplate with a diverging end zone, the end zone of which has a diverging annular flow space which has a ratio A.sub.s /A.sub.e between the exit area and entry area of at least 1.2, and a ratio between the length 1 of the lower edge of the annular exit space of the diverging zone and the width e of the straight section of said annular space which is less than 5; the extrusion operation being carried out in the presence of a liquid lubricant which is incompatible with said thermoplastics material at extrusion temperatures, said lubricant being present at the level of the external wall and at the level of the internal wall of said flow space. Tubes which are manufactured by way of this method are particularly resistant to a high degree of bursting and have an improved surface quality.
In a process for the manufacture of tubes by extrusion of a thermoplastic material charged with discontinuous fibers through a drawplate comprising an annular diverging end section having an exit zone and entry zone and a substantially non-diverging annular straight section contiguous with the exit zone of the diverging end zone, thereby forming an annular flow space, said straight section having a channel width e and length 1, the improvement wherein said diverging end section has an annular area of its exit zone, A.sub.s, of at least 1.2 times the size of the annular area of its entry zone, A.sub.e, and a ratio between the length 1 of the inner edge of the annular straight section and the channel width e of the annular straight section of less than 5, wherein the extrusion of said thermoplastic material through said drawplate is effected in the presence of at least one lubricant consisting essentially of a liquid substance of low viscosity and incompatible with said thermoplastic material at temperatures employed during the extrusion operation, said lubricant being present at the surface of the outer wall and at the surface of the inner wall of said flow space and, wherein the angle .theta. formed by the axis of the flow path of the straight section with the axis of the flow path of the diverging end section is 60.degree. to 90.degree..
Apparatus comprising a drawplate, having a diverging element and a straight section contiguous therewith creating an annular flow space having an internal and external wall, which can be fitted on an extruder drawplate, said diverging element comprising a diverging flow space, with an annular entry zone which has an area A.sub.e, and an annular exit zone which has an area A.sub.s, wherein the ratio of the surface areas A.sub.s /A.sub.e is at least 1.2, the ratio between the length 1 of the inner edge of the straight section and the channel width e of the straight section is less than 5, and, for the purpose of directing a lubricant towards the external wall of said flow space, said drawplate has a bore 3 communicating with a distribution channel 4 which has an opening 5 which opens out onto said external wall, and, for the purpose of directing said lubricant towards the internal wall of said flow space, has an axial channel 6 communicating with a distributing channel 7 which has an opening 8 out over said internal wall and wherein the angle .theta. formed by the axis of the flow path of the straight section with the axis of the flow path of the diverging end section is 60.degree. to 90.degree..
In a process for the manufacturing of tubes be extrusion of a thermoplastic material charged with discontinuous fibers through a drawplate comprising an annular diverging end section and a substantially non-diverging straight section contiguous with the exit zone of the diverging end section forming an annular flow space, the improvement wherein at least one lubricant, consisting essentially of a liquid substance of low viscosity and incompatible with said thermoplastic material at temperatures employed during the extrusion operation, is introduced in the drawplate at the interface between the thermoplastic material and the surface of the outer wall of said flowspace and introduced in the drawplate at the interface between the thermoplastic material and the surface of the inner wall of said flow space.
Apparatus comprising a drawplate, having a diverging element and a straight section contiguous therewith creating an annular flow space having an internal and external wall, which can be fitted on an extruder drawplate wherein for the purpose of directing a lubricant towards the external wall of said flow space, said drawplate has at the junction of the drawplate and extruder drawplate, a bore 3 communicating with a distribution channel 4 which has an opening 5 which opens out onto said external wall, and, for the purpose of directing said lubricant towards the internal wall of said flow space, has at the junction of the drawplate and extruder drawplate, an axial channel 6 communicating with distributing channel 7 which has an opening 8 out over said internal wall.
Dependencies are inferred from the claim text.