A liner tube (1) for rehabilitating sewers and water drainage ducts, with an inner film tube (2), a first layer (4) arranged thereon made of nonwoven material, and a second layer (6) made of glass fiber material and arranged on the layer (4) made of nonwoven material, is characterized in that the first layer (4) contains at least one overlapping wound strip made of nonwoven material, which is impregnated with a fluid reaction resin which can be cured by light or heat, and in that the second layer (6) contains at least one first strip (6a) which is impregnated with a fluid reaction resin and made of glass fiber material, which has glass fibers (8) extending in the longitudinal direction of the liner tube. The invention furthermore relates to a method for producing a liner tube of this kind.

A liner tube (1) for rehabilitating sewers and water drainage ducts, with an inner film tube (2), a first layer (4) arranged thereon made of nonwoven material, and a second layer (6) made of glass fiber material and arranged on the layer (4) made of nonwoven material, is characterized in that the first layer (4) contains at least one overlapping wound strip made of nonwoven material, which is impregnated with a fluid reaction resin which can be cured by light or heat, and in that the second layer (6) contains at least one first strip (6a) which is impregnated with a fluid reaction resin and made of glass fiber material, which has glass fibers (8) extending in the longitudinal direction of the liner tube. The invention furthermore relates to a method for producing a liner tube of this kind.

A method of continuously forming an axially extensible and retractable hose comprising: continuously forming an axially extending helix with axially spaced reinforcing coils from extruded thermoplastic material having a uniform cross-section along its length; and continuously bridging between an adjacent pair of the reinforcing coils with a continuous web of extruded thermoplastic material of substantially uniform width and relatively thin cross-section to form a continuous, helically extending sidewall, with the web having one of two opposite edge regions bonded continuously to a relatively flat outer bonding surface of a radially outwardly located portion of one of the adjacent pair of reinforcing coils, with the web having the other of the edge regions bonded continuously to a relatively flat inner bonding surface of a radially inwardly located portion of the other of the pair of reinforcing coils, and with the edge regions continuously radially separated from each other by the helix.

A method of continuously forming an axially extensible and retractable hose comprising: continuously forming an axially extending helix with axially spaced reinforcing coils from extruded thermoplastic material having a uniform cross-section along its length; and continuously bridging between an adjacent pair of the reinforcing coils with a continuous web of extruded thermoplastic material of substantially uniform width and relatively thin cross-section to form a continuous, helically extending sidewall, with the web having one of two opposite edge regions bonded continuously to a relatively flat outer bonding surface of a radially outwardly located portion of one of the adjacent pair of reinforcing coils, with the web having the other of the edge regions bonded continuously to a relatively flat inner bonding surface of a radially inwardly located portion of the other of the pair of reinforcing coils, and with the edge regions continuously radially separated from each other by the helix.

A method of continuously forming an axially extensible and retractable hose comprising the steps of continuously forming an axially extending helix with axially spaced reinforcing coils from extruded thermoplastic material having a uniform cross-section along its length; and continuously bridging between an adjacent pair of the reinforcing coils with a continuous web of extruded thermoplastic material of substantially uniform width and relatively thin cross-section to form a continuous, helically extending sidewall, with the web having one of two opposite edge regions bonded continuously to a relatively flat outer bonding surface of a radially outwardly located portion of one of the adjacent pair of reinforcing coils, with the web having the other of the edge regions bonded continuously to a relatively flat inner bonding surface of a radially inwardly located portion of the other of the pair of reinforcing coils, and with the edge regions continuously radially separated from each other by the helix.

A method of continuously forming an axially extensible and retractable hose comprising the steps of continuously forming an axially extending helix with axially spaced reinforcing coils from extruded thermoplastic material having a uniform cross-section along its length; and continuously bridging between an adjacent pair of the reinforcing coils with a continuous web of extruded thermoplastic material of substantially uniform width and relatively thin cross-section to form a continuous, helically extending sidewall, with the web having one of two opposite edge regions bonded continuously to a relatively flat outer bonding surface of a radially outwardly located portion of one of the adjacent pair of reinforcing coils, with the web having the other of the edge regions bonded continuously to a relatively flat inner bonding surface of a radially inwardly located portion of the other of the pair of reinforcing coils, and with the edge regions continuously radially separated from each other by the helix.

Plastic tubing including a thermoplastic ribbon helically wrapped and heat bonded to itself to form a tubing wall and a thermoplastic reinforcement located helically around and along the tubing wall. At least a thickness of the tubing wall or a size of the thermoplastic reinforcement is varied along the tubing wall.

A plastic tube has an inner tube, a stiffener layer, and an outer tube. The inner tube is arranged the support organ. A corrugated stiffener preform is formed with corner area walls shaped thinner than the other walls. The preform is fed upon the inner tube to form a stiffener layer that advances with a certain pitch upon the inner tube. The corner parts of every stiffener yield and the brush angle () between the lamellas of the outside gets greater than the corresponding brush angle between the lamellas of the inner side. The stiffener is joined to the inner tube with a melted plastic layer and fed upon the stiffener plastic tape joined to the stiffener with a melted plastic layer. Between the settled edges of the plastic tape a spiral weld joint is formed so that the plastic tape forms the outer tube.

A strip assembly helically windable to form a pipe is disclosed. The strip assembly includes a pair of joined elongate strips, each strip having a strip width and a strip height and each strip including: a base; at least one longitudinal rib upstanding from the base; a pair of spaced apart longitudinal parallel edges; and an angled joining end surface. Each joining end surface has a joining width, the joining width at least 5% greater than the strip width. Also each joining end surface has a joining height, the joining height at least 10% greater than the strip height. The additional joint area provided by the angled joining end surfaces provides a significantly stronger joint.

A method for producing a tubular underwater pipe including: assembling a structure of peripheral metal elements (3A, 3B, 3C) wound in an S-Z configuration about a central flexible core (1) as the core is driven in movement along its longitudinal axis; providing an inductive sensor (12) arranged for rotation about the central flexible core (1) in a manner synchronized with the longitudinal movement of the core so that the sensor scans the periphery of the structure opposite and in the immediate proximity of peripheral elements wound about the core and during the assembly step; using the sensor (12) to acquire measurement signals (S) of which the amplitude varies according to whether or not the sensor (12) is located opposite a peripheral element during the rotation of the sensor (12); and using the measurement signals to control the positioning of the assembled peripheral elements.