Abstract: A circuit for monitoring the temperature of the contacts of an electrical switching device (such as a circuit breaker), comprises an electrical analogue circuit of the thermal characteristics of the switching device. The analogue circuit comprises electrical resistance and capacitance, interconnected so as to form an electrical model of the heat flow paths and capacitances respectively, in the switching device. The preferred embodiment also provides a temperature sensing device to introduce to the analogue circuit a voltage signal the magnitude of which is proportional to the exterior temperature of the switching device. The analogue circuit is connected in a series circuit relationship with a current controller. The current controller controls the amount of current flowing through the analogue circuit. The current controller is in turn controlled by a voltage control signal proportional to the amount of current being carried by the switching device.

Abstract: A tape printer which is for use with pressure-sensitive paper tape and which prints characters in the form of dots disposed in a 7.times. 7 or 7.times. 5 matrix has its printing elements formed by a stack of seven metal strips. Each of these strips has an associated electromagent and upon energization of any one of these electromagnets the associated strip is moved longitudinally to cause the paper tape to be squeezed between an end of the appropriate strip and a rectilinear edge of a fixed anvil so as to cause a dot to be printed. The dimensions of such a dot are determined in one direction by the width of the operated strip and in the other direction by the width of the edge of the anvil. An electric motor is provided to advance the tape.

Abstract: In a side by side refrigerator-freezer appliance, thermal leakage between the compartments is reduced by forming the liners separately for each compartment, but without the partition wall. Adjacent edges of the liners are spaced apart and desirably out-turned to form a truncated V groove. A partition wall is separately formed and foam insulated; edges of the partition are upset to form a tongue slidable along the groove whereby the partition is retained in position.

Abstract: A protective relay arrangement for an A.C. power system wherein the occurrence of a fault is detected by monitoring the phase or amplitude relation between at least one pair of signals which, when a fault occurs in the system, are functions of a current and/or voltage which would have occurred in the power system if the or each emf source in the system had a value equal to the pre-fault voltage at the point in the system where the fault has occurred.

Abstract: An axial gap, disc type, dynamoelectric machine has a stator housing, field pole structures located inside the housing at angularly spaced intervals, and a discoidal rotor. The field pole structures alternate with interpolar spaces. Fluid directing means are provided for inducing vortical fluid flow enhances heat transfer from the rotor to the housing.This invention relates to means for improving the cooling of axial gap, disc-type dynamoelectric machines, and in particular to means for inducing vortical flow of the cooling fluid in the interpolar spaces.Dynamoelectric machines of the general character suitable for embodiment of this invention are of the axial gap, disc-type such as, for example, the machine described in the applicant's United States application Ser. No. 534,058 filed Dec. 26, 1974, Eric Whiteley.

Abstract: A circuit for monitoring semiconductor junction temperature includes means for obtaining a signal representing the current flowing through the semiconductor, a current controller, an electrical analog of the thermal system of the semiconductor, a direct current supply, and a voltage level detector. The current controller is connected in circuit with the analog and the combination to the d.c. supply. The current conducted by the controller via the analog is controlled by the signal such that the voltage across the analog indicates junction temperature and this voltage is monitored by means of the level detector.

Abstract: An alternating current generator of the kind having a superconductive direct current field winding wherein: the field winding is carried on the stator; the armature winding is carried on the rotor; shaft and current collection from the armature winding is effected via a liquid metal slip-ring arrangement. The invention also provides a liquid metal slip-ring arrangement, for use with dynamo electric machines, comprising a first annular member which rotates with the machine rotor, and a non-rotating second annular member which is electrically connected to the first annular member via the liquid metal of the slip-ring arrangement, and arranged to move axially with the first annular member during axial movement of the rotor.

Abstract: A receiver for use in a signalling system of the kind in which data is conveyed by transmitting a signal having alternately first and second frequencies. The receiver has circuitry for providing in response to the received signal two trains of pulses with frequencies corresponding to that of the received signal. The trains of pulses are fed to delay and coincidence detecting circuits which are so arranged that a first coincidence gate circuit produces an output only when the received signal has its first frequency and a second coincidence gate circuit produces an output only when the received signal has its second frequency.

Abstract: Pushbutton telephone subscriber's apparatus in which there is provided a light pen arrangement for reading printed bar-code patterns representing series of decimal digit values, such as telephone numbers, and for converting the signal voltages obtained from reading these patterns to a form which can be signalled by the subscriber's apparatus over an associated telephone line. The bar code patterns may for example be printed in letter headings or in telephone directories adjacent the conventionally printed digit values.

Abstract: A reactor fuel system has fuel pins secured to respective carrier rings as an inner sub-assembly and an outer sub-assembly for mutual telescoping relation, with radial spacing thimbles interconnecting the two assemblies and also permitting interconnection to adjacent assemblies to ensure axial coincidence of cooling flow paths. In the case of booster fuel of annular section, which may be rod-mounted for ready insertion into and withdrawal from the reactor core, the center passages of respective pins are brought into axial alignment to foster effective coolant circulation therethrough.

Abstract: In a two or more stage isotope separation plant using hydrogen sulfide and water in hot and cold exchange zones, for the separation of deuterium (heavy water), in which one first stage portion passes isotope enriched fluid in the form of gas to a second dual temperature isotope concentration stage, the enrichment throughput of the second stage is supplemented by also passing isotope enriched liquid to the second stage. This permits enlargement of an existing plant by expansion of the first stage capacityonly, and providing carry-over of enrichment to the unenlarged second stage in the form of gas and liquid.This invention is directed to an isotope separation process, and to apparatus for carrying out the process. In particular the invention is directed to the separation of deuterium oxide from water, using a water-hydrogen sulphide counterflow arrangement.

Abstract: Apparatus including a telephone instrument for connection to a public telephone system has provision for a call connection to be set up through the system to just a single party upon operation of a single push-button. A plurality of electric switches are preset (usually prior to installation of the instrument) to characterize the directory number of the party that can be called. Upon operation of the push-button, electronic circuitry scans the switches characterizing the directory number to cause the decimal digits of that number to be written sequentially into storage circuitry which subsequently generates a train of impulses in respect of each such digit for transmission to line. There is provision for the scanning operation to be halted for a predetermined period after some of the digits have been written into the storage circuitry.

Abstract: A double-rope winch, which is designed for supporting a load such as a lantern carriage from the top of a high mast, has a primary drum which receives one of the ropes and is provided with driving means to which a winch-operating tool can be connected, and a secondary drum which receives the other rope and is connectable to the primary drum through a linkage including engageable means, so that both drums can be driven together for raising and lowering the load when said drums are connected by the engageable means but so that when the latter is not engaged the primary drum can be driven by itself for balancing the load. The linkage may consist of an endless band passing round both of a pulley keyed to the secondary drum drive shaft and a pulley which is rotatable on the primary drum drive shaft and is provided with dogs which can be drivably engaged or not, as required, by a winch-operating tool applied to the primary drum drive shaft.

Abstract: Long chain polymer flow promoting additives including guar gum, polyethylene oxide and polyacrylamide used to maintain Newtonian flow characteristics in an extended velocity range are mixed into a neutral density liquid having a significant variation of electrical conductivity with the dilution of the neutral density liquid, to provide a stable additive mixture. The concentration of the neutral density carrier liquid when diluted as a working liquid in use within a machine or system may be readily determined by measuring the electrical conductivity of the working liquid, thus permitting the working liquid content of flow promoting additive to be readily determined and controlled.

Abstract: A disc-shaped armature consists essentially of a flat, circular array of overlapping coils bonded together by means of a resinous material to provide a rigid discoidal structure having a disc portion containing the coil sides and inner and outer concentric ring portions containing the coil end-heads. According to the invention the discoidal structure is provided with at least one commutator on the outer ring portion of the structure.

Abstract: A rotor for a dynamoelectric machine comprises a discoidal winding of conductors bonded together by means of a resinous material. The structure has a flat disc portion containing the coil sides and outer and inner ring portions containing the coil end-heads and other end connections. Surfaces on the discoidal structure have formations which interrupt areas exposed to the cooling fluid in the machine. This enhances heat transfer from the winding conductors to the fluid.

Abstract: In a hydrothermal process for manufacturing crystals of metal carbonates, including single crystals of lead carbonate of the cerussite crystalline form, the nutrient material consists of a carbonate or basic carbonate of the said metal, the solvent medium consists of a 0.5 to 5.0 molar aqueous solution of an alkali metal bicarbonate, and the heating is carried out in an autoclave under controlled temperature conditions such that the exterior of the autoclave wall adjacent to the nutrient and the solvent medium in the vicinity thereof is maintained at 200.degree. C to 400.degree. C, and that the exterior of the autoclave wall adjacent to the region of the solvent medium remote from the nutrient is maintained at 170.degree. C to 315.degree. C and at a temperature from 5.degree. C to 150.degree.

Abstract: An ultrasonic transducer apparatus for sensing flow velocity through a pipe wall has a pair of strap-on transducer assemblies for securing to an unprepared pipe surface, the energy coupling between each transducer unit and the pipe or other working device being provided by an elastomeric contact pad, which also facilitates rapid replacement of the transducer crystal, by simplified assembly.

Abstract: Ramp signals having rounded starts and finishes are provided through the method of producing an electrical voltage signal comprised of approximately circular portions and approximately straight line portions wherein the straight line portions are approximately tangential to the circular portions. In achieving the desired ramp signals, suitable circuitry is provided in which, in one embodiment, a high gain amplifier is selectively fed a step input voltage to initiate the ramp signal. The amplifier has a voltage limited output and is series connected to a first integrator. The first integrator has a voltage limited output and is series connected to a second integrator which produces the required ramp signal. The circuit also contains two feedback loops. The output from the first integrator is fed to the input of the high gain amplifier via an inverting amplifier. The output of the second integrator is fed to the high gain amplifier via a resistor.

Abstract: A circuit for operating an electric discharge lamp wherein a change in the mode of operation of the circuit is effected in response to a change of phase of a voltage or current in the circuit which occurs during operation e.g. when the lamp strikes or as the lamp runs up to full current.