Abstract: A cooling mechanism for power semiconductors comprises a metallic evaporator (1) filled with a heat-carrying fluid and designed to be brought into close contact with one face of a smeiconductor (2); at least one condenser constituted by a tube (5) whose inner wall bears a capillary structure, and which is closed at one end and extended at the other end by a conduit (7) of insulating material; and an envelope (8) enclosing the tube (5) and attached at the upper part of the conduit (7) so as to create a chamber (11) for the circulation of a cooling fluid, with the conduit (7) being connected to the evaporator (1) by an elastic piece (14). The pressure inside the assembly constituted by the evaporator (1), the condenser(s) (5) and the conduit (7) is lower than atmospheric pressure, and cooling is effected by an evaporation-condensation cycle.

Abstract: The present invention is concerned with an anti-backlash device for a pump shaft comprising an asymmetrical idler (3) pivoting around a fixed axis (4) and an elastic device (5) which produces a restoring force that tends to press the idler (3) against the surface of the pump shaft (1). The anti-backlash device further embodies at least one fin (7) firmly attached to the idler (3) and preferably arranged nearly perpendicular to the direction of flow of the pumped fluid, so that the motion of the fluid will produce a force which, when applied to the fin, yields a moment with respect to the idler axis slightly greater than that produced by the restorative force applied in the opposite sense.

Abstract: The invention concerns a Doppler radar kinemometer intended to measure the speed of a railway vehicle. According to the invention, it includes two antennas (1,2) mechanically connected to one another such that their axes form a determined angle between them. This angle is preferably between 60.degree. and 120.degree.. For safety operation, the antennas are each supplied with ultrahigh frequency waves (F1,F2) by their own wave generators (4,5), and each furnishes corresponding Doppler frequencies (Fd1,Fd2) to a distinct processing unit (11,12), with the signals coming from these two processing units then processed within a computing assembly (15) which supplies the value of the measured velocity.

Abstract: The invention concerns a process for assembly of the end of a girder (16,18',18",20', 20"and the associated region of a crossbrace (10,12), constituting components of the chassis end of a railway vehicle, with the girder and crossbrace each comprising at least one vertical web and upper and lower flanges. According to the invention, the flanges of the girder are cut away such that its web extends longitudinally beyong the edges of the flanges. Then the flanges of the crossbrace are cut so as to form attachment journals with free edges adapted to the respective free edges of the flanges of the girder, at the same time, forming in the region of the free edges, hook-shaped lateral appendages. The crossbrace and girder are positioned so that the respective free edges of the flanges of the crossbrace and the girder essentially abut one another, and the girder and crossbrace are welded together in the regions of mutual contact.

Abstract: A device for continuous production of heat and cold comprises a combination of an external heat source (10), at least first and second units (1, 2) each of which operates by using different solid-fluid adsorbent-refrigerant pairs, and each of which includes two reactors (11, 12; 21, 22) containing the same solid adsorbent, a condenser (13, 23) and an evaporator (14). The reactors of the first unit (1) are connected alternately to the external heat source (10) and the heat recovered from the first unit (1) is used to heat alternately the reactors of the second unit (2). Heat may be tapped at the condensers, and cold may be tapped at the evaporators.

Abstract: A mechanism for anti-seismic connection between the pump base and the dome of a nuclear power station is characterized by the fact that the pump base (1) is equipped externally with a flange (3) seated with a slight axial play and significant radial play within a socket (4) which is a fixed cover closed by and able to slide axially with a slight play within a cylindrical reinforcement (7a) of the dome (7). A radial damping mechanism (8) is installed between the flange (3) and the socket (4) to permit slow displacements between these two entities, but to block abrupt displacements. The lower end of the socket (4) comprises a collar (15) equipped with a metallic journal (16) which can slide axially within a bearing (17) firm with the internal wall of the dome (7).

Abstract: The present invention concerns a process and a circuit enabling determination of the last intermediate node of a pathway comprising a minimum number of nodes from the m-th node to the n-th node in a network comprising p nodes interconnected by a number of links (p being a positive whole number). The process includes steps of iterative matrix calculation and comparison of elements of the same rank of certain matrices, and is especially suitable for communications networks constituted by a number of geographically separated nodes connected to one another by communications lines.

Abstract: The invention concerns a process for control of the opening of a power interrupter, especially a transistor, at a determined instant, regardless of the particular characteristics of the interrupter. According to the invention, the emission of the normal closing command (A) of the interrupter is terminated at a determined time interval before the said determined instant, and in its place is emitted an additional closing command (G) with a duration equal to the difference between the said interval and the actual time required by the interrupter to pass from the closed state to the open state. Preferably, the actual time required by the interrupter to change state is determined during its preceding passages from the closed state to the open state.

Abstract: The invention concerns a thermic machine comprising a reactor of the adsorption-desorption type, a condenser and an evaporator. According to the invention, the machine is constituted by a first vertical hermetic cylindrical tank section (1), traversed by a first hydraulic circuit (4) and containing the reactor, an envelope arranged at the periphery of the first tank section (1), which is connected to a second hydraulic circuit (6) and which together with the wall of the said first tank section (1) constitutes the condenser (5), and a second hermetic tank section (2) in communication with and arranged below tank section (1), the second tank section being traversed by a third hydraulic circuit (7) and constituting the evaporator.

Abstract: A power semiconductor column has power semiconductor elements arranged in alternation with thermally and electrically conductive evaporation blocks. Each evaporation block is connected in a separate heat-dissipating fluid circuit. Each fluid circuit has a heat exchanger connected to the corresponding evaporation block by way of a pair of flexible, electrically insulating fluid connections. Heat-carrying dielectric fluid circulates within each circuit between the evaporation block and the heat exchanger, cooling of the semiconductor elements being effected by evaporation of the fluid in the evaporation block and condensation of the fluid in the heat exchanger.

Abstract: The invention concerns a process and an apparatus to initiate the reversal of an inverter controlling the placement of a so-called hands-free telephone set in a reception mode or a transmission mode. According to the invention, the position of the inverter (8) is a function of the sign of the difference between the amplitudes of the integrated analog emitted signal and the integrated analog received signal. By preference, the received signal is drawn downstream (from the received-signal output) of the inverter, while the emitted signal is drawn upstream (from the emitted-signal input) of the inverter (8). A second received signal is drawn upstream of the inverter (from the received-signal input) so as to nullify the delay imparted to the change in position of the inverter if the amplitude of the corresponding integrated signal becomes significant.

Abstract: A system for supply of direct current to at least two electrical loads having a common polarity, especially for power supply to an arc furnace with several electrodes or to plasma generators, comprises a set of load-controlled rectifiers (7) arranged in a Graetz bridge (A, B, C), in parallel upon a common alternating current power supply (5, 6). The half-bridges (A.sub.2, B.sub.2, C.sub.2) situated on the common-polarity side have a common dephasing control voltage, while the half-bridges (A.sub.1, B.sub.1, C.sub.1) situated on the other side are each controlled individually. This mechanism can be used in particular for power supply to arc furnaces or plasma torches.

Abstract: A circuit monitors the period of separation between impulses and provides an output only when the period of separation between successive impulses is substantially the same as a predeterimed period. The impulses are applied to a monostable circuit which produces pulses of fixed duration in response. A switching circuit controlled by the pulses switches a binary counter to be driven by a low frequency oscillator output between pulses and by a high frequency oscillator output during pulses, the counter being reset to zero at the trailing edge of each pulse. A comparator determines whether, before reset, the counter reaches a count corresponding to the predetermined period and provides an output pulse to an AND circuit input when the count is reached. The AND circuit has another input connected to the monostable circuit output and thus provides an output pulse when the comparator output is coincident with a corresponding pulse from the monostable circuit.

Abstract: The present invention involves a thermal compensation procedure for magnetic circuits, such as those used in security devices detecting metallic masses, whose losses increase as a function of ambient temperature. According to the invention a body is placed in the immediate proximity of the magnetic circuit, the body being made of a material whose magnetic permeability is a decreasing function of temperature and whose Curie point equals the maximum possible ambient temperature.

Abstract: The invention provides an elastic compensation chamber, with variable volume, for a huydraulic energy dissipator of the telescopic type in which the elastic compensation chamber (20) is formed by one or more cylindrical sections (21) which only partially surround the working cylinder (1), to create large free spaces permitting an easy circulation of liquid between the said working cylinder (1) and the exterior tube (6) and in all directions, so as to accelerate the elimination of heat and avert a dangerous temperature elevation.

Abstract: A logic circuit produces a direct current signal not exceeding a predetermined maximum intensity at its output terminal regardless of the amplitude of an alternating current signal applied to its input terminal. The circuit includes an AC to DC converter having an output which is non-referenced to ground, a condenser connected between the positive and negative output terminals of the converter, and a constant current generator connected between the positive output terminal of the converter and ground, the negative output terminal of the converter constituting the output terminal of the logic circuit.

Abstract: A thermal energy collector, intended for a system such as a cooling system of the solar type whose mode of operation includes a phase consisting of adsorption of a fluid by a given material and a subsequent desorption phase, comprises a compartment having an upper surface to be exposed to a source of thermal energy and a bottom surface to be connected to a duct joining the compartment to the aforementioned system, with the adsorptive-desorptive material being placed between these surfaces. To increase the efficiency of the adsorptive-desorptive material, a space is provided between the material and the bottom surface of the compartment, with a supporting layer containing openings being placed beneath the material in order to hold it in place against the upper surface.

Abstract: In a computer network having a central computer, a plurality of peripheral computers, and a time-shared common memory accessible to the network computers over a single bus connected to the common memory, an electronic switch of the telephone type is connected to all of the computers so that direct links may be established between respective members of one or more selected pairs of computers. Data is transmitted between computers via the direct links effected by the switch, and the bus is thus primarily reserved for access to the main memory for each of the computers. Direct links for transmitting data from a peripheral computer and another computer are established in accordance with connection orders sent from the peripheral computer to the central computer via the common memory. If the other computer is available to receive data, the central computer instructs the electronic switch to connect the peripheral computer directly to the receiving computer.

Abstract: The invention concerns a control apparatus for an arc furnace (1) comprising at least one electrode (2), and powered with direct current from an alternating current electric power source (4), through the intermediary of a controlled-rectifier converter (3).According to the invention, this apparatus includes a loop (24) for rapid control of the reactive energy drawn from the alternating current power source (4), and a circuit (15) for limitation of the maximum intensity of the direct current flowing in the electrode (2). Preferably, the rapid control of the reactive energy is obtained by holding essentially constant the product of the intensity in the source (4) and the sine of the dephasing angle. It includes in addition a loop (13) for slow control generating a reference signal of the reactive energy applied to the said rapid control loop (24), and limiting the variation of the reactive energy.

Abstract: A two terminal control switch having a main switch and a saturable current transformer whose primary winding is series connected with the main switch. A center tapped full wave rectifier has a capacitor connected between its DC sides, such capacitor also being connected to a junction between the primary winding and the main switch.