Abstract: A process for fabricating a foamed plastic product. The process includes a plastic film that is prefoamed in order to introduce lamellar discontinuities such as prefoamed bubbles. The film is pressurized by a gas under a positive pressure causing the gas to diffuse into the film, forming a second film. Further, the second film is inflated in order to form the foamed plastic product. The second film is inflated by heating the second film at a temperature below the melting point of the second film and under a reduced pressure.

Abstract: A folded dielectric film element is provided which converts energy. The film element includes at least one dielectric film that is bent into folds and provided with electrodes. The electrodes are arranged in the folds so that different electrodes are placed in successive folds. The strength of an electric field increases in one fold and decreases in a successive fold.

Abstract: The invention relates to a method for processing extrudable material, especially for the manufacture of a multilayer extrusion product in an extrusion device, wherein the extrudable material is brought in solid form, advantageously as powder or in granular form, and which includes a central extrusion channel (1) and the stator means (2, 3) and the rotor (4) defining it. The invention concerns also such an extrusion device. In the extrusion device according to the invention it is used an optional number of stator and rotor means (2, 3, 4) arranged packlike alternately one within the other, whereby the extrudable material is first melted during its feed into an annular feed defile (5) advantageously in conical or double-conical form between the stator means (2, 3) and the rotor means (4) after the infeed thereof before the central channel, and thereafter compressed to the final extrusion pressure.

Abstract: The invention relates to a method of and a device for simultaneously generating heat energy and oscillation energy. In the method heat is generated by induction heating and oscillations are created by means of at least piezoelectric elements. Previously a resonance circuit formed by a series connection of an inductive component and a capacitive, piezoelectric component has been used for the generation of oscillations only. A disadvantage of this kind of circuit has been that the circuit is difficult to control on account of the narrow resonance region of the piezoelectric element. This advantage is avoided in the solution according to the invention in such manner that one and the same resonance circuit formed by a series connection of an inductive and capacitive element generates both heat energy and oscillation energy.

Abstract: The present invention concerns a dielectric film for converting electromagnetic or electrostatic energy into mechanical work, and a procedure for manufacturing the film. The film of the invention consists of a homogeneous film layer foamed to be of full-cell type and which has been oriented by stretching it in two directions and coated at least in part on one side or on both sides with an electrically conductive layer. The film is manufactured by extruding the plastic which has been made to be foamable, into tubular shape, performing intermediate cooling of the tube and reheating it, expanding the heated tube in two directions, metallizing the outer surfaces and cutting the tube open to become a film.

Abstract: A procedure for controlling the imprint in reproductive printing. With a view to providing a versatile printing control system, and one which eliminates the maximum of errors, the invention is mainly characterized in that by means of an optical system is formed an image signal consistent with the imprint and which is compared with a set-point image signal produced in one way or another, from the result of comparison thus obtained being formed an electrical differential signal, which according to the feedback principle controls the formation of the imprint of each object under examination.

Abstract: The invention concerns an extruder head for regulating the temperature of a flow of molten plastic containing a foaming agent. In the flow passage of the extruder head is arranged a mixer which is inductively heated and transfers heat to the plastic flow thereby regulating the temperature thereof during the passage through the extruder head.