Abstract: A method for making a polyethylene jacket on steel pipes including applying an inner foil upon the preheated steel pipe for purposes of providing adhesion thereto and of an outer, jacketing foil, also to be applied through a duel extrusion head which is to be heated to an operating temperature of approximately 170.degree. C. During extrusion, a gaseous mixture is fed to the space between the surface of the tube to be jacketed and the inner foil, which gaseous mixture consists of air to which a reactive gaseous component, such as ozone, has been added; the inner foils is made from a material so that the gaseous mixture reacts under the formation of groups which provide adhesion, such as carboxylic groups.

Abstract: A thermoplastic hose is extruced, longitudinally, but in opposite (thinned) locations, and the resulting two semi-circular sheets are flattened, superimposed with an offset, and wrapped around a rotating and axially advanced pipe. The hose may be extruded from above or from the side. The method and apparatus is applicable also for high-density PE (e.g., 0.95).

Abstract: Steel pipes pass through an extruder with a low-pressure antechamber for obtaining suction of an extruded hose against the pipe. The entrance to that antechamber is sealed by a combination of rubber elastic and spring steel disks, the latter having tongues being deflected by the pipe entering the chamber, and tongues of one disk sealingly cover the slots of an adjacent disk.

Abstract: The roller track for moving large pipes through a tempering furnace includes two pairs of relatively closely spaced, resiliently mounted rollers disposed in the end zone of the furnace, where any portion of the pipe passing through is hot and has minimum strength on account of the heating.

Abstract: An internally cooled mandrel is provided with regularly arranged copper fingers projecting into the inner flow space and leaving a recess adjacent the outer surface which is filled with buildup. These fingers are arranged in axial rows in which the pins are staggeredly positioned.

Abstract: The process for the continuous hardening of tubes comprises helically advancing a plurality of tubes arranged end to end in a horizontal direction and externally heating said tubes. A further step includes simultaneously or successively heating internally the said tubes and subsequently cooling said tubes both externally and internally. A further step includes temporarily accelerating the feeding of said tubes to divide the substantially continuous line of tubes into individual tubes. An additional step before externally and internally heating the tubes includes preheating said tubes to a temperature in the range of 500.degree. to 600.degree. C. Apparatus for the continuous hardening of tubes includes a roller table for the longitudinal helical transport of the tubes arranged end to end. An external heat source is provided for heating the tubes and an external spraying ring is arranged axially in advance of the heat source for the external cooling of the tubes.

Abstract: A steel pipe with longitudinal welding seam is wrapped helically by means of a polyethylene ribbon which is normally stretched, but temporary stretch relief provides for a thicker envelope above and adjacent to the seam. A ribbon deflector roll and a pressure roll provide the stretching through a speed differential which is changed as stretch relief.

Abstract: A thermoplastic coupler sleeve for interconnecting tubes or pipes is made by extruding thermoplastic material, e.g., polyethylene, to make a ribbon, and wrapping the ribbon around a heater coil in as many layers as needed to obtain the sleeve.

Abstract: Large diameter pipes are moved past a preheater, an induction heater, prequench nozzles, a sizing mill and post quench nozzles. An inside quenching head is mounted on a support tube, held against the inside wall of a pipe by rollers right at the sizing stand. The sizing rollers maintain or restore circularity of the pipe concurrently with quenching.

Abstract: Surfaces of thermoplastic parts are welded by placing a star-shaped heating element in-between the parts. The element is a coiled wire jacketed in plastic which melts during the welding. The resulting bond covers a relatively large area. The method is used for providing a saddle flange to a thermoplastic tube.

Abstract: Apparatus for feeding and distributing a steel melt into a continuous casting mould for slabs includes a pouring vessel with outlet apertures in its bottom wall. Immersion outlet elements depend from said vessel in registry with its outlet apertures, and extend down through the bath surface level in the mould and have lateral outlets. A pair of immersion outlets extend into said mould, and have an internal cross-section greater than the apertures in the pouring vessel, with their bottoms closed. Said immersion outlets each have a pair of lateral outlets of different cross-sectional area, on opposite sides thereof, longitudinally offset with respect to each other. One of the outlet apertures is larger in cross section than the other and is directed towards the center of the mould. Smaller outlet apertures are one-third to one-fifth of the cross-sectional area of the larger outlet apertures. Said outlet apertures are directed obliquely upward.