Abstract: An extruded multilayer plastic pipe is provided. The pipe comprises an inner layer, an outer layer and an intermediate layer. Each of the inner and outer layers is comprised of a thermoplastic material. The intermediate layer consists essentially of a lower density material than said inner and outer layers, and the intermediate layer is situated between and abuts both the inner layer and the outer layer. At least one of the inner, outer and intermediate layers consists of reinforced solid or foamed reprocessed plastic.

Abstract: An apparatus for molding plastic including: (a) an injection space; (b) forming apparatus for supplying plastic material to the injection space, the forming apparatus having at least an inner conical stator and an outer conical stator and at least one rotatable rotor disposed outside of the inner conical stator; and (c) a piston for compressing the plastic material supplied to the injection space into a mold to form the plastic material into a shape determined by the mold.

Abstract: An extrusion apparatus and method, and a tubular product and a pipe made of several different materials.

Abstract: The invention relates to a method and an apparatus for manufacturing an extruded plastic product, the apparatus comprising at least one rotor (1) and at least one stator (2, 3) 4 with a feed gap (4) provided between them, a groove (7) being situated on the other side of the feed gap (4), the groove pressing the material to be extruded out of the apparatus when the rotor (1) is rotated. The cross section of the groove (7) remains substantially unchanged. At the opposite side of the feed gap (4) there is positioned a countergroove (8) in such a way that a processing cavity consisting of the grooves (7), the countergrooves (8) and the clearance between 6 them decreases at least partially continuously along 5 the axis of the extruder. The deformation energy of the material can thus be kept as small as possible due to the unchanging cross section of the groove (7), and the material stays in the groove (7) due to the placement of the flights (7a, 8a).

Abstract: A method of steering an aircraft, and an aircraft comprising a supporting structure, at least one utility space, at least two propellers whose axles are arranged horizontally, and a driving mechanism to rotate each propeller. The blade angles of at least one propeller of the aircraft are adjusted as a function of a rotation angle of the propeller such that the blow power of the propellers provides the aircraft with a lifting force, and after take-off of the aircraft the blade angles of the propellers are adjusted such that the blow power of the propellers provides the aircraft with horizontal flight.

Abstract: An aircraft rotor and an aircraft which aircraft has a body and a rotor arranged to it, the rotor having at least two blades. The rotor is arranged to rotate around a substantially vertical axis. The blades are arranged in such a manner that, when rotating, they form a conical surface, whereby to provide ascending force, the ascending force coefficients of the blades are adjusted to be positive and to provide propulsive force, the ascending force coefficients of the blades on the forward side and on the rear side are adjusted to have opposite signs.

Abstract: A method for manufacturing an extrudable product including the steps of (a) providing an apparatus including an extruder having at least one rotor with first grooves, at least one stator with second grooves and a clearance between the rotor and the stator, the first grooves, second grooves and clearance forming a processing cavity having a volume that is equal to the volumes of the first grooves, the second grooves and the clearance, the processing cavity having a cross-sectional area that decreases continuously along at least a part of an axis of the extruder, the extruder further having a supply for feeding a material to be extruded into the processing cavity; b) feeding the material to be extruded in a powder, pellet or granuate form into the processing cavity through the supply and causing rotation of the rotor relative to the stator such that the material is forced to proceed along an x-axis in a shear zone of the extruder where the material is subjected to a shear which causes a fictional heat that melt

Abstract: An aircraft having a frame (1) and at least a rotor (2a, 2b) for providing lift for the aircraft. The aircraft comprises elements for accommodation purposes. Furthermore, solar cells (5) are arranged on the aircraft for exploiting solar energy, and the rotor (2a, 2b) comprises elements for adjusting the rotor (2a, 2b) to exploit wind energy when the aircraft is substantially stationary.

Abstract: An extruder according to the invention comprises at least two annular conical feed gaps (9) one within the other, formed between a rotatable rotor (1) and a stator (4, 5). At lest some of the material to be extruded is subjected in the different feed gaps (9) of the extruder alternately to a higher pressure and then to a lower pressure. The rotor (1) or stator (4, 5) between the feed gaps (9) can then be balanced such that the pressure effect provides a hydrodynamic bearing, whereby, when the extruder is used, even at worst a very small force is exerted on the other bearings of the rotor (1) or stator (4, 5). By the method of the invention, a product can also be produced which contains cross-linked and at least partly oriented polyethylene.

Abstract: Film of dielectric material, which film contains gas bubbles preferably of a flat shape. To achieve improved electrical properties, the film is given a large internal unipolar charge, which is created by charging the film by means of an electric field intensive enough to produce partial discharges in the gas bubbles and to cause the charges to move into the dielectric material of the film.

Abstract: A method for extruding an extrudable material to form an extruded product, the method including the steps of (a) providing an extruder having a periphery and at least a first stator, an outer rotor and an inner rotor, the first stator being disposed between the outer rotor and the inner rotor to define at least two annular feed gaps disposed one within the other in a radial direction within the periphery of the extruder, a first of the at least two annular feed gaps being defined by the outer rotor and the first stator and being disposed outside of the first stator between the first stator and the outer rotor with the outer rotor being closer to the periphery than the first stator, the first feed gap being the outermost feed gap in the extruder, the extruder including a supply conduit for supplying the material to the first feed gap through the first stator; and (b) supplying the material to the at least two annular feed gaps, with at least a part of the material being supplied through the first stator to the

Abstract: Film of dielectric material, self-adhesive by virtue of an electrostatic force, which film contains gas blisters preferably of a flat shape. To achieve an adhesive quality of the film, the film is given a large internal unipolar charge, which is created by charging the film by means of an electric field intensive enough to produce partial discharges in the gas blisters and to cause the charges to move into the dielectric material of the film.

Abstract: An extruder having at least one conical stator and at least one rotatable conical rotor. The rotor is mounted from its widest point with first and second bearings in such a way that the first bearing receives the forces acting in one axial direction of the rotor and the second bearing receives the forces acting in an opposite axial direction of the rotor. A method for using the extruder involves feeding a material to the extruder between the rotor and stator and rotating the rotor to cause the extruder to extrude the material.

Abstract: An extruder according to the invention comprises at least two annular conical feed gaps (9) one within the other, formed between a rotatable rotor (1) and a stator (4, 5). At least some of the material to be extruded is subjected in the different feed gaps (9) of the extruder alternately to a higher pressure and then to a lower pressure. The rotor (1) or stator (4, 5) between the feed gaps (9) can then be balanced such that the pressure effect provides a hydrodynamic bearing, whereby, when the extruder is used, even at worst a very small force is exerted on die other bearings of the rotor (1) or stator (4, 5). By the method of the invention, a product can also be produced which contains cross-linked and at least partly oriented polyethylene.

Abstract: An extrusion apparatus including at least one conical stator, and at least one conical rotor. The rotor is adapted for defibering or orienting a plastic material. The apparatus has an opening for receiving an elongate product or mandrel. The product or mandrel may be disposed in the apparatus such that, with the product or mandrel received in the opening, an extrusion conduit is defined in the opening between the product or mandrel and the rotor and stator. The rotor and stator are disposed with respect to one another to form a supply opening wherein the plastic material flows between the stator and rotor and is pressed into the extrusion conduit.

Abstract: A method for making a product to be extruded and an extruder. The extruder has at least two conical stators and at least one conical rotor placed rotatably between the stators. The extruder further has supply conduits for feeding the material to be extruded separately into the exterior and interior of the rotor. Each supply conduit is provided with a separately adjustable feeding device by means of which the amount of material flow to be supplied can be adjusted. The degree to which the space between the rotor and the stator is filled and the amount of the heat generated by friction can be regulated. Further, the ratio of the material flows in the different supply conduits determines the ratio of the thickness of the layers obtained. The method and extruder according to the invention make it possible to regulate the properties of a final product easily and in several different ways.

Abstract: The invention relates to a sensor for measuring acceleration and sound pressure, the sensor comprising a first pressure sensitive film (2) for measuring pressure (P) and second pressure sensitive film (5) having a mass (6) disposed thereon for measuring acceleration (A). The films are arranged concentrically in the same plane, so that pressure and acceleration are measured at the same point, thereby avoiding a phase difference between the two measurements.

Abstract: A multi-layer reinforced and stabilized cable construction comprising a core portion (1, 11) and a non-metallic sheathing portion having barrier and protective layers and two or more outer reinforcement layers. In order for the mechanical and barrier properties of the cable to be controlled, the barrier and protective layers and/or the reinforcement layers (12, 13) are oriented in a controlled manner at different angles by fibrous reinforcements or lamellar barriers.

Abstract: An extruder including: (a) at least two concentric stators including (i) an inner stator having at least an outer surface that is at least mostly conical and (ii) an outer stator having at least an inner surface that is at least mostly conical; (b) at least one rotatable rotor that is at least mostly conical; and (c) a supply conduit for supplying material into a space between the stators. The at least one rotatable rotor being disposed in the space between the inner stator and the outer stator. The at least one rotor includes a plurality of ducts that define passages through which material can flow from the space to an interior of the rotor. Each of the plurality of ducts defines an opening or groove that opens into the space. The supply conduit has a conduit end defining an orifice.

Abstract: A method for producing a homogeneous material with an extruder is provided. The extruder has at least two annular conical feed gaps situated between a rotatable rotor and a stator so that the material to be extruded is supplied between the rotor and the stator. Between the delivery point of the material to be extruded and the nozzle of the extruder in the direction of travel of the material the at least one rotor or stator of the extruder is provided with openings passing therethrough so that at least some of the material to be extruded is made to flow through the openings from one annular conical feed gap to another annular conical feed gap. The invention also relates to an extruder and to a multilayer plastic pipe.