Abstract: An extrusion line for the production of peroxide cross-linked polyethylene pipes includes a cross-linking oven (5, 13) having an actuated deflection roller (7). The cross-linking oven has a first heating section (A) that extends from an inlet to said deflection roller (7) and a second heating section (B) that extends from said deflection roller to an outlet. An element is provided for adjusting a height of the deflection roller (7) and an angle of the first and second heating sections (A, B) relative to a horizontal plane.

Abstract: A method and apparatus for moving along a tube extrusion line. An extruded tube is pushed through the extrusion line, by means of pressure generated by an extruder, to a withdrawal unit that takes over further driving of the tube. In a first-moving along phase, in which the tube has not yet passed a sealing of a calibration cooling unit relative to the atmosphere, the latter is under atmospheric pressure. In a second phase, in which the tube has passed the sealing, the calibration and cooling unit is placed under underpressure. In the first phase, the tube is supported either by internal overpressure or by a mechanical inner guide. A support cylinder extends axially from a casing head of the extruder and extends coaxially into a calibration sleeve in a first section of the calibration and cooling unit. A support plate is disposed between the casing head and an inlet of the calibration sleeve and provides external support for a tube exiting the casing head.

Abstract: A method and extrusion line for producing peroxide-cross-linked polyethylene pipes in an extrusion line having an extruder, a cross-linking furnace and a flue. The extruded tube is subjected to a stretching process, and the cross-linking furnace has a first heating section that extends from its inlet to an actuated deflection roller and a second heating section from the deflection roller to its outlet. The stretching process in the first heating section and the stretching process in the second heating section are monitored and regulated in such a manner that the necessary stretching of the pipe takes place primarily in the first heating section, and the stretching of the pipe in the second heating section is subjected to zero adjustment. In this case, the height of the deflection roller(s) of the cross-linking furnace and the angle of the heating sections to the horizontal plane can be height-adjustable.

Abstract: A method and extrusion line for producing peroxide-cross-linked polyethylene pipes in an extrusion line having an extruder, a cross-linking furnace and a flue. The extruded tube is subjected to a stretching process, and the cross-linking furnace has a first heating section that extends from its inlet to an actuated deflection roller and a second heating section from the deflection roller to its outlet. The stretching process in the first heating section and the stretching process in the second heating section are monitored and regulated in such a manner that the necessary stretching of the pipe takes place primarily in the first heating section, and the stretching of the pipe in the second heating section is subjected to zero adjustment. In this case, the height of the deflection roller(s) of the cross-linking furnace and the angle of the heating sections to the horizontal plane can be height-adjustable.

Abstract: A method and apparatus for moving along a tube extrusion line. An extruded tube is pushed through the extrusion line, by means of pressure generated by an extruder, to a withdrawal unit that takes over further driving of the tube. In a first-moving along phase, in which the tube has not yet passed a sealing of a calibration cooling unit relative to the atmosphere, the latter is under atmospheric pressure. In a second phase, in which the tube has passed the sealing, the calibration and cooling unit is placed under underpressure. In the first phase, the tube is supported either by internal overpressure or by a mechanical inner guide. A support cylinder extends axially from a casing head of the extruder and extends coaxially into a calibration sleeve in a first section of the calibration and cooling unit. A support plate is disposed between the casing head and an inlet of the calibration sleeve and provides external support for a tube exiting the casing head.

Abstract: A method and extrusion line for producing peroxide-cross-linked polyethylene pipes in an extrusion line having an extruder, a cross-linking furnace and a flue. The extruded tube is subjected to a stretching process, and the cross-linking furnace has a first heating section that extends from its inlet to an actuated deflection roller and a second heating section from the deflection roller to its outlet. The stretching process in the first heating section and the stretching process in the second heating section are monitored and regulated in such a manner that the necessary stretching of the pipe takes place primarily in the first heating section, and the stretching of the pipe in the second heating section is subjected to zero adjustment. In this case, the height of the deflection roller(s) of the cross-linking furnace and the angle of the heating sections to the horizontal plane can be height-adjustable.

Abstract: Device for extruding hollow strands from thermoplastic material, with an extruder head, having a mandrel, and a calibrating device, for making a dimensional change while production is in progress, and with a radially adjustable inlet, at least one Ranque vortex chamber being formed in the mandrel, the cooling air outlet of which chamber leads into a cooling tube, which extends as an axial extension of the mandrel through the inlet of the calibrating device and has a cooling air outlet opening out into the calibrating device. This device achieves the object of providing a device with which effective interior cooling is achieved in calibrating devices designed for making a dimensional change while operation is in progress.

Abstract: Infinitely adjustable calibrating shell includes a central piece formed by strips or bands which are hingedly connected to each other and intersect like an extendable lattice that is formed into a shell. Preferably, the ends of the strips are movably connected to annular heads. The inner diameter of the central piece which is decisive for the calibrating process, can be modified by axially changing the distance between the annular heads, the cross section of the central piece having a circular shape in each axial position. The infinitely adjustable calibrating shell is suitable for continuous extruded plastic parts, in particular plastic pipes.

Abstract: Infinitely adjustable calibration sleeve for extruded plastic pipes includes an inlet head and two strap layers that intersect like a lattice grate and that are linked with each other at the crossing points. In that manner, the inlet head and the strap layers are adjustable to the pipe diameter, and the inlet head has radially adjustable overlapping segments in a radial plane distributed over the perimeter of the plastic pipe to be calibrated, and the segments mesh and have slots in their overlapping areas. Further, the faces of the segments are configured to lie on the plastic pipe to be calibrated, and the strap layers are linked to the segments flush with the faces. Such a calibration sleeve effectively seals the vacuum tank from the environment and prevents deformations of the entering, extruded plastic pipe.