Abstract: A method of producing a plate-like construction having a double-wall structure and its use. According to the present invention, several elongated profiles which have essentially straight central axes are arranged against each other in such a way that adjacent hollow profiles abut each other and together form, in general terms, a flat stack having two opposite sides. The hollow profiles are welded together in order to join them with welded seams, in which case the welding is essentially carried out simultaneously from both sides of the stack. Besides good flexural strength and the opportunity to recycle, thermoplastic plates which are produced by means of the present method exhibit resistance to corrosion, decay and mould.

Abstract: A method of producing a plate-like construction having a double-wall structure and its use. According to the present invention, several elongated profiles which have essentially straight central axes are arranged against each other in such a way that adjacent hollow profiles abut each other and together form, in general terms, a flat stack having two opposite sides. The hollow profiles are welded together in order to join them with welded seams, in which case the welding is essentially carried out simultaneously from both sides of the stack. Besides good flexural strength and the opportunity to recycle, thermoplastic plates which are produced by means of the present method exhibit resistance to corrosion, decay and mould.

Abstract: The invention relates to a method and a device for cooling an extruded thermoplastics pipe (1) by directing a gaseous cooling medium tangentially towards the inner surface of the thermoplastics pipe (1) along its whole periphery, whereby the interior of the thermoplastics pipe (1) is divided by means of a protecting pipe (8) into an outer ring-shaped flow channel (9) for the cooling medium along the inner surface of the thermoplastics pipe (1), and a central return channel (10) through which a part of the cooling medium is intended to be sucked back influenced by the flow of cooling medium in the outer ring-shaped flow channel (9), and to be redirected towards the inner surface of the thermoplastics pipe (1).

Abstract: The invention concerns a method and device for joining thermoplastics pipes manufactured by spiral winding of a hollow profile. The method according to the invention is characterized in that a welding mirror (5) adaptable to the prepared end surfaces of the pipes and provided with heating means, is inserted in the slot between the pipes (1), the pipe ends are pressed against the heated welding mirror to heat the thermoplastics material at the end of the pipe ends to a welding temperature to render the plastics material on the joint surface plastic, the welding mirror (5) is removed from between the pipes, the heated pipe ends are pressed against each other so that the thermoplastics materials melt together to form a welded joint, and the welded joint is allowed to cool. The welding mirror (5, 5?) according to the invention is characterized in that the welding mirror is adaptable to the shape of the end surface of the pipe cut along a radial side wall (6) of the hollow profile.

Abstract: The invention relates to a method and a device for cooling an extruded thermoplastics pipe (1) by directing a gaseous cooling medium tangentially towards the inner surface of the thermoplastics pipe (1) along its whole periphery, whereby the interior of the thermoplastics pipe (1) is divided by means of a protecting pipe (8) into an outer ring-shaped flow channel (9) for the cooling medium along the inner surface of the thermoplastics pipe (1), and a central return channel (10) through which a part of the cooling medium is intended to be sucked back influenced by the flow of cooling medium in the outer ring-shaped flow channel (9), and to be redirected towards the inner surface of the thermoplastics pipe (1).

Abstract: A method and system are provided for improving the quality in positron emission tomography (PET) images. Image quality may be improved by pre-normalizing dynamic PET images and then applying a multivariate analysis tool on the images to generate improved quality dynamic PET images. The dynamic PET images are the images reconstructed from the raw dynamic PET data in the image domain of the PET study. A first normalization method is a data treatment (also referred to as noise pre-normalization) for the negative values that may result from the image reconstruction and/or from random variations in detector readings. A second normalization method is background noise pre-normalization where background pixel values are masked. A third normalization method is kinetic pre-normalization where the contrast is improved to allow greater visualization of the activity in the image. Multivariate analysis such as PCA may then be applied to each slice of the dynamic PET images.

Abstract: A method for preparing an end of a thermoplastics tube (1) is provided, wherein the tube is manufactured by spirally winding and welding together of a hollow profile (1a) having a substantially rectangular cross section. The method includes the following steps: cutting the end of the tube by a planar transversal section; extruding a second hollow profile (2) having a rectangular cross section and an outer shape essentially similar to Fat of the hollow profile (1a) from which the tube (1) is manufactured; spirally winding the extruded second hollow profile (2) around a drum having a diameter corresponding to inner diameter of the tube (1); cutting a loop (2a) from the second hollow profile (2) in a length corresponding to circumference of the tube end; joining the ends of the loop (2a) to each other, whereby a ring (2b) is formed having the same inner and outer diameters as the spirally wound tube (1); placing the ring (2b) against the cut tube end; and welding the ring (2b) to the tube end.

Abstract: A method for joining thermoplastic pipes made by spiral winding a hollow profile with mainly rectangular cross section.

Abstract: The present invention relates to a welding method in the manufacture of a spirally wound tube having a thermoplastic profile (1) of a mainly rectangular cross-section. A hole profile (1) is wound in a screw line form manner on a welding drum (2) simultaneously as profile surfaces (1a, 1b), which are to be welded together are heated with hot air to a desired temperature, whereafter a welding mass (S) is extruded onto the heated profile surfaces (1a, 1b) in two streams along each edge of the profile surface (1a, 1b) and the welding mass coated hole profile portions are pressed together by means of a press roller (10). The invention is characterized in that the welding is performed with a welding head (3) coupled to an extruder and provided with a welding keel (4), which from the outside is inserted between two profile surfaces (1a, 1b) to be welded together. Hot air (L.sub.1, L.sub.

Abstract: The present invention relates to a surgical stretching device for the expansion of tissue, in particular for the expansion of skin. The invention is characterized in that it includes one or more threads (1) or bands (1) extending between two fastening arrangements (2). The fastening arrangements have one-way nips for the threads (1) or the bands (1) so that at least one fastening arrangement (2) can be moved on the threads (1), or bands towards the other fastening arrangement. When this happens, the distance between fastening points on the tissue is reduced such that a stretching of the tissue occurs outside the fastening points.

Abstract: A method for joining spirally wound thermoplastic pipes is disclosed. The method includes providing a first spirally wound thermoplastic pipe and a second spirally wound thermoplastic pipe, wherein each thermoplastic pipe includes a spirally wound hollow profile. The method further includes placing the end of the first thermoplastic pipe against the end of the second thermoplastic pipe such that a gap having a step is formed between the end surfaces, applying a stainless steel band over the gap and heating the steel band, positioning an extruder and a slide and smoothing organ inside the thermoplastic pipes, heating the end surface of the first thermoplastic pipe and the end surface of the second thermoplastic pipe with a heating means, and extruding melted thermoplastic from the extruder and into the gap between the end surfaces and applying pressure to the melted thermoplastic with the slide and smoothing organ.

Abstract: A method for manufacturing a joint pipe from a spirally wound thermoplastic profile is described in which the pipe end to be furnished with a joint pipe is pushed onto a rotatably driven, slightly conical mandrel, after which a melt profile of thermoplast is extruded and spirally wound in overlapping wraps around the mandrel and the pipe end in a direction extending from a point furthest from the pipe end, followed by cooling of the joint pipe, cutting of its end surface, and removal of the pipe end from the mandrel.

Abstract: A spiral-wound tube formed of a hollow section 1 is provided wherein the hollow section is joined together by extruder welding or gluing. The hollow section is coextruded and comprises an outer layer (2) of pastic with a homogenous surface and good weldability. An intermediate layer 3 is provided of a modified polymer and an inner layer (4) is also provided. The interior space defined by the tubular layers (2, 3, 4) is preferably rectangular in cross-section.

Abstract: The invention provides a method of forming composite products of two incompatible plastics or other materials by extruding a first stream of plastic through a die to form a profile and coextruding another stream on the surface thereof which is fusible with the first plastic and is impregnated with foreign matter and causing, by means of high heat, pressure drop or shear stress, a rupture of the layer to form a pattern of irregular cavities and projections to which a coating can be applied which will invade the cavities and surround the projections to bond with the extruded profile.