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 tube support mechanism is adaptable to a respective tube diameter being transported, and includes an articulated link chain that rests against a circumference of a tube, and includes chain links. The chain links are disposed in at least two planes, overlap one another from plane to plane in overlap zones, and are pivotably connected. Facing ends of the chain links of a given plane of chain links have identical gear wheel contours that mesh with one another. Adjustment of the tube support mechanism from one nominal diameter to another is effected by a pressure effect, onto the tube support mechanism, of a conical tube transition piece that results during the change in diameter during continuing operation. An angle of contact of the tube support mechanism against a tube successively changes.

Abstract: An apparatus for producing a mixture of various bulk materials, comprising a weighing device that is carried by the framework of the apparatus. A weighing container is suspended or supported by the weighing device, and is adapted to receive a desired mixture of bulk material components from supply containers via an upper inlet. A mixing device extends from above into the weighing container and is driven by motor-transmission means that is mounted on the framework and is gravimetrically separate from the weighing container. The mixing device is permanently suspended on the motor-transmission means free of the weighing container.

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: Apparatus and method for supporting tubes in extrusion lines. A tube support mechanism is adaptable to a respective tube diameter being transported, and includes at least one articulated link chain configured to rest against at least part of a circumference of a tube, and comprises chain links having end faces directed toward the tube. The chain links are disposed in at least two planes, and overlap one another from plane to plane in overlap zones. The chain links are pivotably connected to one another in such overlap zones. Facing ends of the chain links of a given plane of chain links have identical gear wheel contours that mesh with one another. Adjustment of the tube support mechanism from one nominal diameter to another is effected by a pressure effect, onto the tube support mechanism, of a conical tube transition piece that results during the change in diameter during continuing operation. An angle of contact of the tube support mechanism against a tube successively changes.

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.

Abstract: The invention relates to a device for detecting faults in and/or measuring the wall thickness of continuously moving strips, sections or tubes of plastics, using ultrasonic signals. To this end a number of ultrasonic heads (A, B, C, D) with transmitters and receivers are disposed distributed over the width of the strip or section or the periphery of the tube. The signal, emitted by a transmitter of an ultrasonic measuring head (3) and reflected without scatter, is received by the receiver of said ultrasonic measuring head (3), while the scattered signals reflected on the tube, section or the like are received by the receivers of its adjacent ultrasonic measuring heads (A, B). The inclusion of the scattered and reflected signals in the measurement appreciably increases the measured area per measurement in comparison with using exclusively the signal directly reflected without scatter.

Abstract: A device for producing hollow plastic pipes having a predetermined wall thickness, includes an extruder for producing soft hollow plastic tubing from a raw material, a continuous cooling chamber disposed downstream of the extruder for hardening the soft hollow tubing into the desired plastic pipes after the wall thickness of the plastic tubing has been calibrated, an independent water cooled calibrating sleeve disposed between the extruder and the cooling chamber which adjusts the wall thickness of the soft hollow plastic tubing, the water cooled calibrating sleeve being separated from the extruder and the cooling chamber, and a thickness measuring device disposed in the gap between the calibrating sleeve and the cooling chamber. The calibrating sleeve has an inner wall in which are arranged water inlets and suction orifices distributed along the circumference and the length of the inner wall.

Abstract: The invention relates to a wall thickness measuring device for pipes and the like, more particularly of extruded plastics, having a measuring head (15) connected to measuring and supply leads. The measuring head is mounted to be reversed around an opening of passage A for the pipe to be measured by means of a guide (14) attached to a frame having the opening of passage. The measure and supply leads (22-25) are acommodated in two guide chains (20, 21) which extend in opposite directions, partly on an inner guideway (18) and the other part on a guideway (19), connected thereto, of a guide core member (17). The guide core member (17) is basically constructed in the form of a portion of a circle and is disposed concentrically of the opening of passage (5) and can be moved therearound.

Abstract: The invention relates to a material feed device for an extruder. The material feed device has a storage container (4) suspended with provision for free movement on measuring members (3) of a mass throughput weighing device. The outlet (13) of the storage container (4) discharges into an inlet (5) of a feed unit (6) of the extruder. The outlet (13) and the inlet (5) are sealed off on the outside by a seal (16) enabling the storage container (4) to move freely in relation to the inlet (5). The seal comprises a rigid ring bearing via a sealing lip (17) against the outside of the tubular outlet (13) and borne via a sealing lip (18) on a flat sliding surface (15) of the inlet (5). While the sealing lip (17) bearing on the tubular outlet (13) enables the storage container (4) to make a vertical movement, the sealing lip (18) bearing on the flat surface (15) enables the storage container (4) to make a horizontal movement in both axes in relation to the inlet (5).