Abstract: An object of cross-linked polymer, such as insulation for a cable conductor or a cable sheath, is formed by using a starting material containing a peroxide and a polymer material with the ability to undergo a cross-linking reaction in the presence of peroxide. The reaction is carried out during at least a part of the process in the presence of a substance which has the ability to undergo a color change during the cross-linking reaction of the polymer material so that a color change of the substance is obtained. There may also be added a dye which does not have the ability to undergo a color change during the cross-linking of the polymer material. The substance may be an aromatic compound containing at least one halogen atom and/or at least one heterocyclic ring in which ring there is at least one nitrogen atom to which no hydrogen atom is linked.

Abstract: For joining two cables which have an insulation of a cross-linked linear polymer such as polyethylene, the insulation on each of the two ends to be connected is tapered, the ends of the conductors are then secured to each other, and the joint is wrapped with a tape of the same linear polymer containing a cross-linking agent. The wrapping is enclosed in a tube of relatively rigid material, which is then enclosed in a tube of flexible material. The joint is then enclosed in a casing and simultaneously subjected to heating by an electric heating arrangement and to all-sided pressure exerted by a fluid, which may be a gas or a liquid such as silicone oil.

Abstract: In a hydraulic press which has an expansible pressure cell arranged in a cavity and a pad of elastic material for forming workpieces, with a trough-shaped supporting member for forming tools and workpieces, displaceable into and out of the press, the press includes a second pressure cell arranged below the trough-shaped supporting member, positioned in a cavity formed between two discs which form supporting members for the trough-shaped supporting member.

Abstract: An industrial robot has a movable arm and a tool mounted on the arm and connected thereto so as to be movable with at least one degree of freedom relative to the arm, and transducers are arranged to sense the position of the tool relative to the arm and to regulate control means for the positioning of the tool. The connecting means may permit movement in a plurality of directions, and this movement takes place against prestressed spring members so that movement only takes place when the force causing the movement exceeds a minimum value.

Abstract: In a press for hydrostatic extrusion, the die has a conical inlet portion and a portion forming a die opening. The die has draining channels which bypass the smallest cross-section of the die opening for the purpose of intercepting and diverting pressure medium which accompanies the billet as it moves down towards the smallest cross-section of the die. This removes any pressure medium which might otherwise pass through the die opening and damage the surface of the extruded article.

Abstract: A compound billet for extrusion by isostatic liquid pressure which has a core and a casing with a gap therebetween is produced by applying a sealing ring with greater thickness than the gap between the core and the casing around the rear end of the core, then inserting the core into the casing, and pressing the sealing ring to stick in the gap between the core and the casing so that the sealing ring and/or the casing are deformed. The rear end of the casing is beveled inwardly.

Abstract: A rectifier station for high voltage direct current transmission includes a rectifier bridge with a control system. In order to limit the direct voltage of the station in the event of disturbances, the control system is provided with arrangements for sensing the direct voltage of the station and the derivative of such voltage. The arrangement supplies signals to limit the voltage increase of the station when the voltage and derivative exceed given values by increasing the delay angle of the station.

Abstract: A press for hydrostatic extrusion includes a pressure chamber for enclosing a pressure medium which is formed of a high pressure cylinder, a pressure generating piston, a die and a die support and seals. The die support includes an exchangeable support ring which engages the end surface of the liner and bridges the gap between the liner and the die. A metallic sealing ring is arranged within the liner in engagement therewith, forming a gap between the inner surface of the sealing ring and the outer surface of the die or die support. The die support has a groove in its upper surface which contains a sealing member against which the edge of the metallic sealing ring engages. The lower outer corner of the metallic sealing ring is bevelled to form a space which communicates with the outside of the press.

Abstract: For hydrostatically hot pressing bodies of borides, carbides or nitrides of titanium, zirconium or chromium from a powder having an excess of boron, carbon or nitrogen, the power is enclosed in a sealed container of a material which forms compounds with boron, carbon or nitrogen which have a melting point at least equal to that of the material of the container. Container materials may be for example metals from Group IVb of the Periodic System, particularly titanium and zirconium or their alloys in the case of titanium or chromium compounds and zirconium or zirconium base alloys in the case of zirconium compounds. This allows pressing at temperatures of up to 1700.degree.-1800.degree. C, which is high enough to cause bonding between the powder grains.

Abstract: A metallurgical furnace vessel is provided with means for injecting fluid into a melt in a vessel, the fluid carrying materials reactive with the melt and incidentally causing rapid erosion of the vessel's wall portion above the location where the fluid is injected. This wall portion is provided with cooling means and is made so that it can be removed for repair or replacement.

Abstract: A pressure furnace for treating products at high temperature and high pressure includes a high pressure chamber formed of a vertical high pressure cylinder with end closures projecting into the cylinder and a press stand with a window aperture which is somewhat larger than the height of the high pressure chamber when the end closures are fully inserted for enclosing the high pressure chamber during the pressing operation. A support member is provided which holds the pressure chamber in such a position that gaps are formed between the press stand and the end closures when the latter are moved into their innermost positions in the chamber. The lower end closure is at least in part removable and includes a bottom portion provided with cooling channels, with a stationary and a movable connection unit for connecting the bottom portion to a coolant source. The movable unit is displaceable between a connected position in contact with the stationary connection unit and a release position.

Abstract: A direct-cooled layer winding for transformers is formed of a plurality of helically wound tapes, the tapes in successive layers being directed backwards and forwards in the axial direction so that the turns of successive layers form angles with each other. At least one cooling layer is arranged coaxial with the winding between two of the tape layers. The cooling layer is formed of a tubular cooling conductor which is helically wound into a complete layer with the inlet and outlet at the opposite ends of the winding.

Abstract: A magnetic separator for a hot mixture has an enclosure with a bottom having means for fluidizing the mixture which travels through the enclosure from an entrance to an exit. Within the enclosure an internally water-cooled drum rotates and which is internally provided with magnetizing means so that magnetic particles in the fluidized flow, into which the drum dips, is picked up and through a suitable discharge carried out of the enclosure, other material in the mixture and which is non-magnetic, discharging from the enclosure. Internally the drum has means for maintaining a body of water in the drum's portion which dips into the fluidized flow, the flow of hot mixture causing the water to vaporize and cool that portion of the drum.

Abstract: A DC arc furnace of the type having an arcing electrode and a withdrawable starting electrode for initially forming electrical contact with a charge of metal pieces, and an electric connection for a subsequently formed melt in the furnace, has a DC power source positively connected directly with the starting electrode and the melt connection, and negatively connected with the arcing electrode. When initially charged with solid metal pieces, the starting electrode is contacted with the charge so that an arc is formed between the pieces and the arcing electrode until a melt is formed for contact with the connection for the melt. With both the starting electrode and melt connection directly connected positively with the power source, without intervening control equipment, the current automatically commutates from the starting electrode to the melt connection as the melt forms so as to contact the latter.

Abstract: In a current supply system for wheeled vehicles which includes a DC generating device and substantially parallel running over-head lines provided with current collectors, a closed AC circuit is provided which is independent of the current collector and includes an AC generating device which feeds the over-head lines, as well as a device connecting the lines together. The DC and AC generating device includes a first rectifying device which is connected to a three-phase AC network and a generating DC network with a superposed AC component.

Abstract: An electric arc furnace for DC operation has an electric connection for a melt in the furnace's hearth, in the form of an elongated metal connector having a refractory enclosure exposing an inner end of the connector for contact with and incidental melting by the melt, with means for cooling the connector between its inner and outer ends and removing heat at a rate preventing the connector from melting throughout its length to its outer end. The connector has a cross-sectional area large enough to carry the current required for forming a heating arc between an electrode and the surface of the melt, and the connector has similar composition as the melt as exemplified by a steel connector for a steel melt.

Abstract: An asynchronous machine with a rated power of at least 1 MVA has a laminated stator core which supports a multiphase AC winding and a rotor surrounded by the stator core and having a length substantially greater than the length of the laminated stator core. The rotor has winding slots running axially along its whole length, each of the slots having wall portions facing each other and converging radially outward in connection with a central plane. Winding bars are arranged in the winding slots and are included in a squirrel-cage winding and fit the slot walls. An annular winding portion at each end of the rotor short-circuits the rotor bars, such winding portion lying axially within the end surface of the rotor core and outside the end surface of the stator core. The bars may be U-shaped in cross-section, with one flange of each adjacent pairs of bars located in the same winding slot. The end portions of the rotor core have annular grooves therearound.

Abstract: A cylindrical elongated furnace for treating material at high temperature in a gaseous atmosphere under high pressure includes a vertical cylindrical pressure chamber for confining gas under pressure and a furnace space surrounded by a cylindrical heater formed of electrical resistor elements and insulation surrounding the furnace space and the heater. The insulation is formed by a cylindrical insulating sheath. The heater is built up of ceramic elements which form a cylinder with annular channels for the electrical resistor elements and supporting insulation surrounding and holding the ceramic elements together, such insulation having a low gas permeability and being formed of several layers of a tight felt impregnated with a hardening component. The leads for the heating elements are flat vertical elements arranged on the outside of the ceramic elements and formed with one or more bights projecting into the annular channels to reduce the free hanging length of the leads.

Abstract: A press for hydrostatic extrusion of tubes includes a die having a die opening therein and a mandrel projecting into the die opening and forming therewith a gap for shaping the tubular billet into a tube. The mandrel includes a carrier with a bore therein and a tip inserted in and filling the bore of the carrier. The tip includes an outer sleeve of hard metal and a core filling the sleeve formed of a material which has approximately the same E-modulus of the material of the carrier, such as steel. The inner end of the sleeve is enlarged and the front part of the carrier is compressed around the tip to fix the tip axially in the carrier.

Abstract: A reluctance-type machine arrangement includes a stator with salient poles and a rotor with salient poles surrounded by the stator, the number of stator poles being twice as great as the number of rotor poles. The stator is provided with a working winding and a first magnetizing winding connected to a constant voltage source. Each of the windings includes a number of two-pole coils each of which surrounds two stator poles located immediately one after the other in a peripheral direction. The two-pole coils of the first magnetizing winding are displaced by a stator pole pitch with respect to the two-pole coils of the working winding. A second magnetizing winding is provided which drives the flux along the same flux path and with substantially the same distribution between the various flux paths as the flux driven by the first magnetizing winding. The second magnetizing winding is series-connected to at least a part of the working winding by controlled rectifiers.