Tight flexible pipe

Claim 2

A tight flexible pipe comprising at least one flexible sheath, at least one first flexible armouring withstanding crushing stresses, said flexible sheath ensuring the internal tightness of the pipe and being in contact with one of the internal and external walls of said first armouring and at least one second armouring, surrounding the assembly constituted by said flexible sheath and said first armouring, said second armouring withstanding tractive and/or bending stresses applied to the pipE and comprising at least one layer of preformed rods which are helically wound with a high winding pitch, said rods having such a profiled cross-section that the walls of adjacent rods of said layer which face each other delimit between each other substantially confined spaces and wherein each of said space is filled with a resilient material ensuring the tightness of the pipe between said rods of said layer of said second armouring.

Claim 3

A flexible pipe according to claim 1, wherein said resilient material adheres to said walls of said rods which delimit said substantially confined spaces.

Claim 4

A flexible pipe according to claim 2, wherein said material filling said substantially confined spaces provided between the consecutive rods of said layer constituting said second armouring has, in the temperature range of utilization of the flexible pipe, an elasticity modulus, with respect to twisting, from 5 to 500 kg/cm2.

Claim 5

A flexible pipe according to claim 3, wherein said material has a resistance to traction of at least 50 kg/cm2 and preferably more than 90 kg/cm2.

Claim 6

A flexible pipe according to claim 4, wherein said material has a resistance to tearing of at least 10 kg/cm2.

Claim 7

a flexible pipe according to claim 5, wherein said resilient material filling said confined spaces is made of a polydienic elastomer.

Claim 8

A flexible pipe according to claim 6, wherein said resilient material filling said confined spaces is polychloroprene.

Claim 9

A flexible pipe according to claim 6, wherein said resilient material filling said substantially confined spaces is a sequenced polymer of butadiene and styrene.

Claim 10

A flexible pipe according to claim 1, comprising a first separating layer covering substantially the whole internal wall of said layer.

Claim 11

A flexible pipe according to claim 9, wherein said separating layer is formed by the helical winding of a thin strip, with overlapping of the adjacent convolutions formed by said strip.

Claim 12

A flexible pipe according to claim 10, wherein said separating layer is made of a material which adheres neither to the resilient material filling said substantially confined spaces nor to said profiled rods.

Claim 13

A flexible pipe according to claim 11, wherein said separating strip is made of polyethylene glycol terephthalate.

Claim 14

A flexible pipe according to claim 11, wherein said separating strip is made of high density polyethylene.

Claim 15

A flexible pipe according to claim 11, wherein the proportion of filaments in said matrix is of at least 30 percent per volume.

Claim 16

A flexible pipe according to claim 1, wherein said second armouring comprises two layers of rods, helically wound in opposite directions with a high pitch, comprising a single thin separating layer covering substantially the whole inner wall of the outermost layer of said second armouring and wherein said substantially confined spaces delimited between adjacent rods of said outermost layer are filled with a resilient material which adheres to the walls of the rods defining said substantially confined spaces.

Claim 17

A flexible pipe according to claim 1, wherein the cross-section of each of said rods, has, with respect to a transverse axis passing through its centre of gravity, a moment of inertia whose value is greater than the values of the moment of inertia of this cross-section measured with respect to the other axes passing through the centre of gravity of this cross-section and wherein each of the rods is so positioned that the radius of the pipe passing through the centre of gravity of the cross-section of the rod is perpendicular to said transverse axis.

Claim 18

A flexible pipe according to claim 16, wherein the ratio between the moment of inertia of the cross-section of each rod, with respect to said transverse axis, and the moment of inertia of this cross-section, with respect to the radius of the pipe which passes through the centre of gravity of said cross-section and is perpendicular to sAid transverse axis, is from 1.5 to 2.

Claim 19

A flexible pipe according to claim 1, wherein said rods have a substantially I-shaped cross-section whose central part is positioned substantially along a radial direction with respect to the flexible pipe.

Claim 20

A flexible pipe according to claim 18, further comprising in the central part of the I-shaped cross-section, to establish communication between the adjacent substantially confined spaces.

Claim 21

A flexible pipe according to claim 1, wherein said rods with a profiled cross-section are metal rods.

Claim 22

A flexible pipe according to claim 1 wherein the profiled rods are made of a resin provided with a reinforcement constituted by substantially parallel filaments having a high elasticity modulus and which are not substantially twisted.

Claim 23

A flexible pipe according to claim 21, wherein the resin constituting said matrix is a thermosetting resin.

Claim 24

A flexible pipe according to claim 21, wherein the resin constituting said matrix is a thermoplastic resin.

Claim 25

A flexible pipe according to claim 21, wherein the filements reinforcing the resin are continuous filaments.

Claim 26

A flexible pipe according to claim 21, wherein the filaments reinforcing the resin are glass fibers.

Claim 27

A flexible pipe according to claim 25, wherein the glass fibers are pretreated so as to adhere to the resin.

Claim 28

A flexible pipe according to claim 21, wherein the fiber of high elasticity modulus which reinforces the resin is a continuous organic fiber having an elasticity modulus of at least 700,000 bars.

Claim 29

A flexible pipe according to claim 27, wherein the organic fiber is so pretreated as to adhere to the resin.

Claim 30

A flexible pipe according to claim 27, wherein said organic fiber is a carbon fiber.

Claim 31

A flexible pipe according to claim 21, wherein the filaments reinforcing the resin are metallic wire.

Claim 32

A tight flexible pipe suitable as drill pipe, comprising an electrically insulating flexible tubular core providing for the internal tightness of the pipe, a first armouring resisting to crushing stresses, formed by the helically winding, with a small pitch, a strip around said tubular core, a flexible electrically insulating sheath covering said first armouring and a second armouring withstanding tractive and/or torsional stresses applied to the pipe, said second armouring covering said flexible sheath and being constituted by two layers of preformed rods, said layers being helically wound in opposite directions with a high winding pitch, said tubular core and said sheath being made of polyamide 11, the rods of each layer of said second armouring having such a profiled cross-section that the walls of consecutive rods delimit between each other substantially confined spaces and each of said spaces being filled by a resilient material capable of ensuring the tightness of the pipe between said adjacent rods.

Claim 33

A tight flexible pipe suitable as drill pipe, comprising an electrically insulating flexible tubular core providing for the internal tightness of the pipe, a first armouring resisting to crushing stresses, formed by the helically winding, with a small pitch, a strip around said tubular core, a flexible electrically insulating sheath covering said first armouring and a second armouring withstanding tractive and/or torsional stresses applied to the pipe, said second armouring covering said flexible sheath and being constituted by two layers of preformed rods, said layers being helically wound in opposite directions with a high winding pitch, said tubular core and said sheath being made of polyamide 11, the rods of each layer of said second armouring having such a profiled cross-section that the walls of consecutive rods delimit between each other substantially confined spaces and each of said spaces being filled by a resilient material capable of ensuring the tightness of the pipe between said adjacent rods.

Claim 34

A flexible pipe according to claim 31, wherein said profiled rods have a substantially I-shaped cross-section whose length is oriented substantially along a radius of the pipe.

Claim 35

A flexible pipe according to claim 31, comprising two separating layers formed by the winding of a thin layer of a material containing polyethylene glycol terephthalate with partial overlapping of the successive convolutions, one of said separating layers being interposed between said sheath and said second armouring, and the other layer separating the two layers of rods constituting said second armouring.

Claim 36

A flexible pipe according to claim 31, wherein said substantially confined spaces are filled with a resilient material adhering to said walls of the rods and constituted by a polychloroprene elastomer containing reinforcing and vulcanizing charges in suitable proportions for obtaining the desired mechanical and thermal properties.

Claim 37

A flexible drill pipe according to claim 31, comprising power and/or data transmission lines, said lines being housed in at least one of said substantially confined spaces and being embedded in said resilient material filling said substantially confined spaces.