Abstract: In the device disclosed, a load is energized from energy-carrying lines. A detector responsive to a cyclically recurring physical condition, such as daylight, places a switch either in an operating mode or an idling mode in response to the absence of the condition. A control shifts from an idling mode to an operating mode in response to the detector being in a given one of its modes and shifts back to the idling mode after a given time less than the period of the cyclically recurring physical condition. A circuit responds to the control being shifted to its operating mode in response to the given one of the modes of the detector and responds to the detector simultaneously being in the operating mode so as to connect the lines to the load.

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: An arrangement for the production of ingots from high-melting metals, such as steel, by electroslag-remelting is disclosed. A water-cooled ingot mold including a bottom plate forms the solidifying ingot, the ingot being a solidifying portion and a liquid sump. A self-consuming electrode extends into a layer of molten slag covering the liquid sump. An a.c. source is connected between the plate and self-consuming electrode. The mold is adapted to be raised in a known manner. At least one tubular auxiliary electrode is provided with a plasma-forming gas. A d.c. source is connected to the auxiliary electrode and the bottom plate of the mold, the d.c. source being independent of the a.c. source. Various forms of the auxiliary electrode are described.

Abstract: A principal winding is wound around two cores made of soft magnetic material. The principal winding has N turns. Wound around only one of the two cores is a magnetizing winding. A decoupling amplifier of gain v.sub.1 energizes the magnetizing winding via the amplifier output, and the amplifier has an input across which is applied the voltage across the principal winding. The magnetizing winding has v.sub.1.N turns. If the principal winding and the magnetizing winding have the same winding direction, then the gain of the decoupling amplifier is chosen positive. If the principal winding and the magnetizing winding have opposite winding directions, then the gain of the decoupling amplifier is chosen negative.

Abstract: An electroslag remelting plant comprises a cooled mould with a base plate mounted on a car, and an electrode holder secured to a stringer with the help of a carriage. The electrode holder incorporates a standard head made up of two parts isolated from each other, each being adapted for holding in place at least one electrode and secured in the electrode holder so that each part contacts an appropriate contact plate of the electrode holder, the contact plates being connected to unlike poles of a power supply source.

Abstract: An audio range siren detector utilizes an audio pickup including an A.G.C. amplifier, a plurality of electronic active filters having closely spaced resonant frequencies such as 800, 825, 850 timing means responsive to an actuating signal from one of the filters for generating a time slot signal of short duration, gating means responsive to each of the filter means for producing an actuating signal, control logic responsive to the occurrence of all actuating signals within the time slot to produce output denoting a valid siren signal, and relay means for setting traffic lights to emergency condition.The detector includes counters and additional timers to further restrict the conditions under which a valid siren signal will be responded to in order to better discriminate against extraneous ambient noises of all types.

Abstract: Electric power, transmitted to a typical building by lead-in wires and distributed throughout the building by branch lines from which only a fraction of such power is available at each existing branch outlet, is re-combined in an electric branch-line combiner which incorporates two or more electric input plugs, that fit into and receive power from two or more selected branch outlets, and contactor-selector means which relate voltage polarities and phases of the interconnected branch outlets and input plugs and channel the combined power transmitted through such two or more plugs into a single combiner outlet.

Abstract: Lightning protection means for aircraft structural components includes thin, perforated, dielectric and metallic layers applied to the ordinarily lightning-accessible surfaces of composite structures. Where the outer metallic layer of the lightning protection means is formed from sprayed metal, ground connection means to the metallic layer preferably comprises a section of wire screen fused with the sprayed metal on the dielectric layer, a thin metal plate brazed to the wire screen, and a metal attachment connecting the metal plate to adjacent ground structure. Composite-to-metal or composite-to-composite structural joints are protected by making the entire bonded and bolted interface areas conductive for transfer of lightning current, or by isolating the bonded interface area to control the transfer path of the lightning current through the bolted interface area only.

Abstract: An electrical resistance furnace installation, especially for the production of silicon carbide, has no side walls. In the one arrangement, the installation has two end walls, each provided with an electrode, with the resistive core for heating reacting valves extending between the electrodes at the end wall. In another arrangement, the installation has only one end wall, with the resistive core extending between an electrode in the one end wall, and a connection to a further electrode arranged in the bottom of the furnace. In a still further arrangement, the furnace has neither end walls nor side walls, and the resistive core is horizontally supported above the furnace floor and electrically connected through electrodes in the bottom of the furnace. The reacting ballast, in each embodiment, is poured onto the furnace floor to surround the resistive core for heating of the ballast.

Abstract: An artificial neutral voltage derived from the voltages on both energized lines of a three-wire, single-phase energy supply system is compared to the voltage on the neutral line. Comparator means energize interrupter means to cause the cessation of a current flow in the energized lines of the circuit in the event the neutral line voltage is more than a predetermined value above or below the artificially derived neutral voltage for protection in the event an open neutral line condition occurs even when loads are not attached to the energized power lines.

Abstract: An electric furnace wall construction is provided and comprises a plurality of layers of heat insulating fiberboard overlying each other. Certain of the layers of fiberboard are apertured to receive ceramic hangers which support a serpentine arrangement of electric strip resistance heaters. The construction is held together by a plurality of studs and mating locking washers.

Abstract: Electric power dissipation in a mass of molten glass is increased in a controlled manner where two or more power sources are each connected to at least two electrodes in the molten glass, by cross connecting the sources through a controller so that electrodes connected to each source and at proper potentials during a portion of each power signal period are connected together. The interconnection enables a substantial increase in voltage applied to localized regions of the molten glass without requiring higher voltage sources. Adjustment of the controller as the conductivity of the glass increases avoids runaway conditions. Interconnection of single and three phase power sources is disclosed.

Abstract: The roof of the heating chamber in a refractory furnace is made of refractory or brick with vertical holes therein and a number of hooks or holding means are suspended in these holes. The hooks project into the heating chamber and an electrical heating element means is suspended on the hooks. In order to remove the heating elements, a plastic bag is used which has its open edge fastened to the top surface of the furnace to enclose an opening in the furnace through which the heating element and the bricks or holding means to which the heating element is attached can be withdrawn. The bag is of sufficient size to enclose the entire assembly when withdrawn from the furnace. The parts are arranged so that another element can be placed in the furnace by another bag so that gaseous contents of the furnace are kept in the furnace.

Abstract: An electric arc furnace has an anodic contact or hearth electrode and a cathodic arcing electrode, and the furnace is rotative about its vertical axis while the arcing electrode remains stationary in its lateral direction. With a melt in the furnace, the DC arc can be directed in different angular directions with respect to the inside of the furnace.

Abstract: An electric arc furnace has its side wall lining protected against arc-flare by an external magnet forming a magnetic flux field on the inside of the lining where arc-flare protection is required, and a supply of ferro-magnetic particles are fed downwardly through this flux field for the purpose of forming a layer of the particles held against the lining. The particles are continuously fed to replace particles which, because of heating, become non-magnetic and fall. In this case, the magnet is an electromagnet having an iron core and solenoid windings which produce a more uniformly and widely spread layer of the particles on the side-wall lining's inside.

Abstract: A method of anticipating electrode failure by monitoring the current, voltage and resistance between electrode pairs in a Joule effect heating system. A relatively rapid change in monitored resistance is an indication of an incipient failure. Alarm indicators, instruction print out, and/or process controls can be actuated in response to a given current voltage or resistance change. Plural electrode pairs are monitored by multiplexing to provide a repetitive cyclic scan of the parameters between pairs. Distortion of current and voltage values is minimized, where selective portions of regular power pulses are gated for control of heating, and complex waveforms result by employing true r.m.s. values of current and voltage developed in true r.m.s. to d.c. converters.

Abstract: A high temperature unitary electrical resistance heater which is mechanically supported throughout its active length but spaced from a refractory base with the heating element being substantially free of the supporting structure to provide an efficient heater having relatively low thermal inertia while being rigidly supported for high temperature operation. A flat continuous electrical resistor ribbon is disposed in a multiple loop configuration having a plurality of spaced heater segments with flat confronting surfaces and a plurality of legs outwardly extending from an edge of the ribbon and secured within a refractory base to support the ribbon in spaced relation to the refractory base.

Abstract: A high temperature unitary electrical resistance heater which is mechanically supported throughout its active length but spaced from a refractory base with the heating element being substantially free of the supporting structure to provide an efficient heater having relatively low thermal inertia while being rigidly supported for high temperature operation. A flat continuous electrical resistor ribbon is folded in a multiple loop helix-like configuration formed of a plurality of straight segments and a repetitive array of folded, overlapped corner portions. A strut is interposed within each folded corner and welded therein, outwardly extending end portions of each strut being rigidly secured in a refractory base structure with the resistor ribbon being spaced along its active length from the base structure.

Abstract: A direct arc electric furnace having a tiltable base for pouring molten metal from the furnace. A refractory lined hearth supported by the base is pivotal with respect to the base for tilting to a degree greater than that capable by the base. The furnace includes shell refractory lining material supported upon the hearth encompassed by a removable shell. Replacement of the shell lining is accomplished by removing the shell, collapsing the shell lining into the hearth, and tilting the hearth with respect to the base sufficiently to dump the collapsed lining from the hearth into the pit adjacent the furnace. Further, the use of the tilting and removable hearth permits the hearth to be removed from the base, inverted in the pit, and the refractory lining of the hearth may then be readily removed for replacement purposes.

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.