Abstract: A flat web of sizable thickness made of thermoplastic can be extruded from an extrusion die without a restrictor bar if a thickness D of a restricting passage is made smaller than a shaping distance A of die lips (4, 5), and if at least one wall of the restricting passage (6) is adjustably designed as an elastic lip (7) by adjusting elements (8), so that thickness D and distance A can be changed at the same time by actuating the adjusting elements.

Abstract: Extruded, smooth finished solid sheet or film, which may have a thickness <1 mm, comprised of a thermoplastic plastic (such as polycarbonate) with a glass transition temperature >50.degree. C., which under conditions of orientation displays optical birefringence, may be manufactured into a flat strip with smooth finished surfaces, to yield a strip which has characteristics as follows:optical birefringence path difference less than or equal to 50 nm (single pass);low surface roughness;low variation in thickness; by extrusion of the plastic in a thermoplastic state, through a slot nozzle;wherein during or after the smoothing of the two surfaces one of the surfaces of the strip is cooled to below the glass transition temperature, while the other surface and the predominant part of the interior region of the strip remain in the thermoplastic state and the strip is cooled to below the glass transition temperature, under conditions which minimize the deforming forces on the surfaces of the extruded strip.

Abstract: An extruded, smooth finished solid sheet or film of thickness <1 mm is prepared from a thermoplastic plastic having a glass transition temperature >50.degree. C., by extruding the plastic in the thermoplastic state through a slot nozzle to form a flat extruded strip, which is introduced into the roll gap of a roll stack having a smoothed upper roll and a lower roll, with the upper roll being maintained at a temperature below the glass transition temperature of the thermoplastic plastic and with the lower roll being maintained at a temperature in the plastic state domain of the thermoplastic plastic, and, after exiting the roll gap, the extruded strip is moved resting on a smooth-finished endless belt which passes around the lower roll, thereby smoothing the surface of the strip; and cooling said extruded strip below the glass transition temperature.

Abstract: For producing a multi-extrudate of thermoplastically processable plastic, a coextrusion adapter block has a multi-part slide having a plurality of side-by-side slide sections mutually spaced in a direction transverse to the flow direction and slidably fitted in the adapter block for movement to adjustably protrude into a secondary runner for adjusting the thickness of a molten extrudate therein. A multi-layer extrudate emerging from the adapter block is further extruded in an extrusion die, and the thickness of at least one layer thereof is measured at a plurality of positions along the width thereof. The width measurements are used to control the positions of corresponding slide sections so that the layer thicknesses can be accurately controlled during an extruding operation.

Abstract: Multi-layer plastic elements containing a polycarbonate core, with a polymethacrylate layer containing a UV absorber, and modified to be impact-resistant, applied to the core, where the polymethacrylate plastic layer is composed of methacrylate copolymers, which form compatible mixtures with polycarbonate, especially the polycarbonate of bisphenol A, exhibit good adhesion between the polycarbonate and the polymethacrylate. The methacrylate copolymers are methyl methacrylate copolymers with (meth)acrylic monomers which contain carbocyclic substituents in the ester group. The protective layer containing UV absorber is applied to the polycarbonate plastic in thickness from 1 to 500 .mu.m by coextrusion or by lacquering.

Abstract: A gas-tight joint for pipe linings and risers inside a bore, consisting of a neck with an outside thread and of a matching collar with an inside thread, with a groove in the vicinity of the thread on the collar and/or of the thread on the neck to accommodate a deformable gasket that, when the joint is screwed tight, is demarcated and deformed by the base of the groove in the neck and/or in the collar and by the contour of the thread on the other component. The cross-sectional area demarcated by the base of the groove in the neck and/or collar and by the contour of the thread on the other component once the two components have been screwed together remains constant along the groove and is equal to or larger than the cross-sectional area of the deformable gasket before the components are screwed together.

Abstract: Hollow chamber plates of synthetic material are produced from two thermoplastic cover layers, which preferably have been produced immediately beforehand by extrusion, which are brought into contact with a large number of previously produced webs and welded together. By setting the webs into wavy lines running against each other, a high degree of rigidity in the hollow chamber plate is attained. A device for the production of such hollow chamber plates is described.

Abstract: A method for manufacture of a sealing ring with a flanged sealing lip having hydrodynamically acting return transport properties in which a sealing lip is first generated by extrusion of a plastically deformable material through a ring nozzle having rotating inner and outer surfaces which are rotated relative to each other to impart a helical motion to the extruded material; the hydrodynamically acting return transport properties being a microscopically fine pleating of the surface of the extruded hollow cylinder. The extruded cylinder is then solidified and cut to a predetermined length. The cylinder is then widened in the radial direction at its front end by an assembly tool which shapes the cylinder into a trumpet-shaped sealing ring with a flanged sealing lip.

Abstract: In a method for manufacturing a sealing ring with a sealing lip, the material forming the sealing lip is fabricated in plastically deformable condition into the shape of a column-like hollow body. Prior to solidification, the column-like hollow body is twisted between axially spaced cross-sectional planes. This forms return elements with hydrodynamic action. Subsequently, the hollow body is solidfied and its diameter is enlarged axially outside the region of the sealing lip and it is then secured in a sealing ring housing.

Abstract: Method and apparatus for the continuous industrial production of tubular bodies in which coated or uncoated steel strip is formed to a slit tube and the opposite strip edges are longitudinally seam welded at high speed by a laser beam of high energy density under protective gas with or without supply of additive material, and after a preparation adapted to the narrow melt zone and bringing together of the strip edges a fusion welding with subsequent controlled cooling and upsetting is carried out which results in a seam geometry suitable for any further processing.

Abstract: The purpose of the process and the apparatus of the invention is to face weld extruded thermoplastic moldings the end faces of which lie in a plane and the end face edges of which are juxtaposed in a coplanar fashion. The end faces are pressed against a heatable and coolable plate in which grooves are formed corresponding to the cross-section of the end face. The floor of the grooves is heated up to or above the melting temperature of the plastic. The entry of the grooves is thermally insulated from the floor region and, if necessary, can be cooled. When the end faces are sunk into the grooves, the plastic is melted. The plastic melt, rising in the groove, is cooled until solid in the thermally insulated entry region. Following the welding in the floor region, the floor region is cooled below the melting temperature, and the welded bundle is separated from the plate.

Abstract: Bodies having hollow sections and made of thermoplastic are tightly connected in the front to a molded body of a thermoplastic weldable thereto. The front end piece of each hollow sectioned body is introduced into a corresponding open recess molded in the molded body and having inside dimensions matching the front section of the hollow sectioned body so that the end piece of the hollow sectioned body rests against the wall of the recess. The front side and the edge are then welded to one another on their entire periphery, preferably by sinking into a groove of a welding tool shaped to correspond to the common edge.

Abstract: Heat exchanger or heat accumulator bodies which are simple to produce. The bodies consist of a stack of extruded hollow chamber panels with plane smooth outer walls and webs that join the outer walls in a single piece. The hollow chamber panels are joined to one another in the stack on the front side by locking connections. The locking connections can be produced with an inserted electrical band heater, by glue seams, or by undercut interlockings. The hollow chamber panels are not joined to one another in the in-between areas or are not everywhere joined in the in-between areas.

Abstract: Improved steel profiles having superior material characteristics are obtained by rolling a precipitation-hardenable fine grain steel, cooling it from a final rolling temperature above the A.sub.1 -temperature down to a temperature of about 400.degree. C. in an atmosphere in which it is allowed to overage, whereupon the steel plate or strip is then cooled down to room temperature and cold-processed to form an open profile which can thereupon be converted into a tube by welding together its longitudinally extending edges and which is then subjected to solution-annealing in order-to dissolve coarse precipitants and subsequently further cooled to form finely dispersed precipitants in the profile.

Abstract: A plate heat exchanger, in particular of synthetic material is disclosed consisting of a stack of plates which are corrugated in two directions transverse to each other. The plates are so arranged in the stack that the corrugations of consecutive plates run in equiphase in one direction and in antiphase in the other direction. In the direction of the corrugation in equiphase, perfusable channels pass.

Abstract: A method for production of a multi-layer gap-less steel pipe. An inner pipe and an outer pipe are formed from thermomechanically rolled steel strip with high notched bar impact strength by welding. The individual helical welding seam steel pipes of about the same lengths are matched with a difference of less than about one percent between the outer diameter of the inner pipe and the inner diameter of the outer pipe. The matched inner pipe is inserted into the outer pipe and the pipes are mechanically expanded with diameter control to a preset outer diameter of the multi-layer steel pipe. The resulting multi-layer steel pipe has the inner pipe disposed under compression and the outer pipe layer disposed under stress. The presence of a compression stress in the inner pipe provides a means opposed to hydrogen sulfide stress corrosion.

Abstract: A laser welding process is used according to the invention for the manufacture of a straight seam weld for tubular construction parts of ferritic, Ti-stabilized CR steel x5CrTi12 for exhaust systems in automobiles. This has the advantage that after welding the construction parts can be expanded or compressed by more than 40% of their original dimensions.

Abstract: A method is provided for joining the ends of steel pipes having male and female ends. The pipe is inserted with the male end into the pipe with the female end and a circular seam is welded, which is disposed at the inside of the female pipe for solidly connecting the pipe with the male end to the pipe with the female end. The male end is preferably provided with a ball section and the female end correspondingly with a ball shaped socket for allowing the pipe to be angled at the connection points. The invention provides the advantage that in automatic welding no large head holes have to be dug out.

Abstract: Improved steel profiles having superior material characteristics are obtained by rolling a precipitation-hardenable fine-grain steel, cooling it from a final rolling temperature above the A.sub.1 -temperature down to a temperature of about 400.degree. C. in an atmosphere in which it is allowed to overage, whereupon the steel plate or strip is then cooled down to room temperature and cold-processed to form an open profile [which can thereupon be converted into a tube by welding together its longitudinally extending edges and] which is then subjected to solution-annealing in order to dissolve coarse precipitants and subsequently further cooled to form finely dispersed precipitants in the profile.

Abstract: A method of and device for producing multi-layer pipes by helically winding a plurality of bands loosely arranged one above the other, which are individually withdrawn from a supply, straightened out, trimmed, and in the form of a band loop are conveyed to the forming station at the respective angle of lead-in corresponding to the respective pipe diameter, whereupon the layers are together welded to form a pipe strand which is subsequently cut into individual pipes. All bands are supplied and advanced independently of the irregularities of the respective longitudinal band edge shape in steadily straight lead-in directions, and all band edges are machined together to a possible maximum width in coordination with each other whereupon the bands are driven together while the welding gap is controlled in conformity with their band edge shape merely by pivoting the pipe.