Abstract: A channel induction furnace, particularly for melting aluminum has a pair of U-shaped channels extending downwardly from the bath. The channels have a radial width, measured outwardly from the axis of the core, which is several times the penetration depth in the molten metal for a current of the energizing frequency and the channel section is tapered so that the channel is wider near the core and narrower away from the core. The planes containing the axes of the channels are skewed about an axis of skewing normal to the axis of the core.

Abstract: An apparatus for heating an electrically conductive fluid ohmically by passing an electric current through the fluid between electrodes spaced along a pipe through which the fluid flows. The pipe has an electrically insulating internal liner and is cooled, e.g. by cooling water flowing through a cooling jacket between inner and outer skins of the pipe. The inner skin supports the liner and is perforated to allow intimate cooling of the liner. The cooling prevents heating of the fluid in a layer immediately adjacent the internal liner to such a temperature that the medium would foul the liner.

Abstract: In the heat treatment of aluminium alloy strip, in which hardening of the material is effected by heat treatment to dissolve pre-existing precipitates in the metal matrix followed by quenching and ageing, the electrical conductance of the strip after quenching is measured using a conductivity probe scanned across the width of the strip, the heating being controlled in accordance with the measured conductance so as to obtain uniform electrical conductance across the width of the strip. This measured electrical conductance has a close correlation with the required mechanical properties. A transmitter producing an electromagnetic field is moved across the strip and a receiver, picking up signals due to the eddy currents in the strip, provides an output automatically controlling the movement of flux modifiers of a transverse flux induction heater to control the strip heating.

Abstract: A heater for liquid foodstuffs has a pipe through which the foodstuff flows and electrodes spaced along the pipe to drive a heating current through the foodstuff. In the embodiment, the electrode is a platinum coated cylinder arranged transversely in an enlarged part of the pipe so that electric current flows to the electrode only over a smooth surface portion, entirely within the edges of the exposed electrode surface.

Abstract: To locate a leak in a length of pressure-assisted oil-filled electric power cable, the static fluid pressure is measured at the two ends of the length and the flow into or out of the cable is measured at one end for at least two different pressure supply conditions giving different flow rates while maintaining zero flow rate at the other end of the cable. The measurements are then repeated with zero measured flow rate at said other end. From these measurements, the relationship between flow rate at each end of the cable and the pressure drop between the ends due to flow can be determined and this enables the position of the leak to be calculated. Apparatus for making the necessary measurements is described.

Abstract: A parameter representative of a physical property of a continuously moving metal strip is determined by repetitively generating acoustical shock waves, containing ultrasonic frequencies, and adjacent the strip and measuring the speed of transmission of the shock wave in the strip. An electric spark generator with a collimator feeds the acoustic energy to the strip 10 and four microphones arranged as a first pair on opposite sides of the strip spaced a known distance from a second pair also on opposite sides of the strip pick up the signal transmitted through the strip. The difference between the mean time of arrival at the first pair and the mean time of arrival at the second pair enables the velocity of propagation in the strip to be determined despite movements of the strip transverse to its plane. The velocity of propagation in particular may be used as a measure of Young's modulus and hence, in the case of a material such as aluminium, as a measure of the temperature of heat treatment.

Abstract: Dimensional stability of an electron discharge heating device having electrodes for focussing the discharge current is improved by providing one or more heat pipes for transferring heat from an electrode to cooling fins outside the vacuum chamber. In one embodiment, a second electrode is water-cooled. The improved cooling not only permits of use of a structure which takes a short time to reach thermally stable conditions due to the small heat capacity of the solid material but also permits of different parts of the gun assembly being operated at different temperatures.

Abstract: A compressor for a heat pump using a condensible gas as a working fluid has a lubricant temperature controller comprising a heater for the lubricant in the sump, the heater being controlled by differential pressure responsive means comprising the vapor pressure above the lubricant in the sump with a pressure obtained from a sensor bulb in the sump oil, the bulb containing a solution, in a lubricant of a refrigerant, the refrigerant preferably being the same as the working fluid of the heat pump.

Abstract: A method of disrupting vapor films formed in film boiling in boilers, in which method transient electrical discharges are effected either in the boiler liquid or in a body of liquid in acoustic communication with the boiler liquid. The electrical discharges are effected at one or more selected locations in the boiler to produce shock waves which act on surfaces of the boiler liquid space where vapor films are to be disrupted. By disrupting such vapor films there is enabled an improvement in the heat transfer rates per unit area across the interface between the fire space and the liquid space of a boiler. There are also disclosed various arrangements in boilers for generating these shock waves. Electrical discharges may be effected between a pair of electrodes mounted in the boiler or between an electrode and an adjacent wall of the boiler, and several mounting configurations for electrodes in boilers are described.

Abstract: A fault in a cable comprising at least two conductors is located by applying a single voltage impulse between two conductors of the cable, passing the resultant current wave form through a primary winding of coupling means which comprises said primary winding and a secondary winding, the primary winding being connected in series between the impulse generator and one of said conductors and which obtains the derivative of said current wave form to give a signal output across the secondary winding, and displaying or recording the signal output. The signal output is a pulse of relatively short duration each time a reflection of the voltage impulse returns to the impulse generator. Preferably a digital transient recorder is used for recording the waveform of the resultant reflected signal from the cable.

Abstract: Apparatus for the electrophoretic separation of particulate material from a sludge, slurry or the like has an L-shaped scraper or scrapers mounted on an endless chain for removing the particulate material from the surface of the anode. A cam-driven collector engages the scraper or scrapers to remove the material therefrom so that it falls downwardly to removal means.

Abstract: In a sodium sulphur cell, the cathode current collector in the sulphur/polysulphide cathodic reactant comprises an impermeable tube, e.g. a carbon or graphite tube which is inert to the cathodic reactant and contains a solid metal core, e.g. an aluminium core, and a deformable electronic conductor, e.g. graphite felt, as a conducting interface between the impermeable tube and the core. In a preferred construction, the current collector is axially located within a cylindrical electrolyte tube, the space between the electrolyte tube and impermeable tube containing the sulphur/polysulphides and a graphite felt. The outer surface of the impermeable tube in this case has grooves or recesses to form a sulphur reservoir.

Abstract: For detecting faults on low voltage alternating current electric power distribution cables, recorders are provided, each triggered by a selected occurrence, e.g. a decrease in signal amplitude or a change in the waveform, to cease recording, after a short delay, of the waveform data in digital form, so that a store holds digital data enabling the waveform of the last few cycles covering the period before and after the selected occurrence. Using a voltage gradient technique analysis of the data enables the position of the fault to be located.

Abstract: The contact area between a first phase of a multi-phase system and a liquid second phase of the system is increased by effecting transient electrical discharges between electrodes immersed in the liquid second phase or in a volume of liquid in acoustic communication with the liquid second phase. The first phase can be in the form of a particulate solid, a gas, or a liquid of lower density than that of the second phase. The first phase is mingled with the second phase by a bubbling technique where the first phase has a lower density than the second phase. The hydraulic shock waves produced by the electrical discharges disperse the bubbles or particles of the first phase in the liquid second phase and thus increase the contact area between the phases.

Abstract: Sludge formation is reduced in the continuous production of iron by electrolysis of a ferrous electrolyte in a electrodeposition cell by cooling spent electrolyte returning to a holding or regeneration tank, and heating reconstituted electrolyte returning to the electrode-position cell. By reducing the temperature of the spent electrolyte the rate of hydrolysis of ferric ions to form oxides of iron, called sludge, is reduced, thus increasing the interval between periodic cleaning of the electrolyte regeneration system and the electrodeposition cell. In preferred forms of the invention heat energy is transferred from the spent electrolyte to the reconstituted electrolyte by means of at least one counter flow heat exchanger in the form of a hollow cylinder containing a plurality of tubes made of titanium. There may be a controllable cooling device disposed between the holding tank and the or the last heat exchanger for maintaining the temperature of electrolyte in the holding tank at a selected value.

Abstract: A method of disrupting vapor films formed in film boiling in boilers, in which method transient electrical discharges are effected either in the boiler liquid or in a body of liquid in acoustic communication with the boiler liquid. The electrical discharges are effected at one or more selected locations in the boiler to produce shock waves which act on surfaces of the boiler liquid space where vapor films are to be disrupted. By disrupting such vapor films there is enabled an improvement in the heat transfer rates per unit area across the interface between the fire space and the liquid space of a boiler. There are also disclosed various arrangements in boilers for generating these shock waves. Electrical discharges may be effected between a pair of electrodes mounted in the boiler or between an electrode and an adjacent wall of the boiler, and several mounting configurations for electrodes in boilers are described.

Abstract: In making .beta.-alumina ceramic articles by a fast firing technique in which the green shapes of compressed powder material are sintered by passing them continuously through a tubular furnace, the furnace is sloped upwardly to give convective air flow forwardly through the furnace at a speed not less than the speed of movement of the article or other means are provided for causing such an air flow or flow of other oxygen-containing gas. An induction furnace is described having a rotating tube and automatic temperature control means.

Abstract: In a sodium sulphur cell, the cathode current collector in the sulphur/polysulphide cathodic reactant comprises a carbon or graphite tube containing a solid metal, e.g. aluminum, core and a liquid metal, e.g. tin or a tin-lead alloy, as a conducting interface between the carbon or graphite tube and the core. In a preferred construction, the current collector is axially located within a cylindrical electrolyte tube, the space between the electrolyte tube and graphite tube containing the sulphur/polysulphides and a graphite felt. The outer surface of the graphite tube in this case may have grooves or recesses to form a sulphur reservoir.

Abstract: In a sodium sulphur cell, the cathode current collector in the sulphur/polysulphide cathodic reactant comprises a carbon or graphite tube containing a solid metal, e.g. aluminum, core and a deformable electronic conductor, e.g. graphite felt, as a conducting interface between the carbon or graphite tube and the core. In a preferred construction, the current collector is axially located within a cylindrical electrolyte tube, the space between the electrolyte tube and graphite tube containing the sulphur/polysulphides and a graphite felt. The outer surface of the graphite tube in this case may have grooves or recesses to form a sulphur reservoir.

Abstract: In making beta-alumina ceramic articles by a fast firing technique in which the green shapes of compressed powder material are sintered by passing them continuously through a tubular furnace, the furnace is sloped upwardly to give convective gas flow forwardly through the furnace at a speed not less than the speed of movement of the article or other means are provided for causing such a gas flow. An induction furnace is described having a rotating tube and automatic temperature control means.