Abstract: A method for the detection and evaluation of faults existing on the walls of metal tubes having internal helical ribs includes for each fault signal received by an ultrasonic emitter-receiver ER, the length of the to-and-fro travel completed by the ultrasonic beam corresponding to the signal is determined and after the amplitude of the signal has been compared with a specific threshold, a correction is applied to one of the terms of the comparison, taking into account the length of travel completed by the signal.

Abstract: To stabilize the conditions of electroextraction of zinc in an acidic medium and in the presence of metal impurities, there is added to the electrolyte a surface-active compound comprising a perfluoroalkyl grouping linked to a polyoxyethylene, amine-oxide or betaine hydrophilic grouping.

Abstract: A control circuit of a synchronous motor with two induction windings, including an electrical power supply assembly (5), two oscillators (2,3) whose outputs are connected respectively to the windings of the motor (1), an intermediary circuit (4), connected on one side to the power supply and on the other to the oscillators, and a central unit for control of the thyristors.The electrical power supply assembly (5) delivers a current of a given unique polarity, and has its output terminals connected by means of a freewheel branch including at least one freewheel diode (6) whose cathode is connected to the positive terminal.

Abstract: The invention relates to a refrigeration device using solar energy. This device includes a refrigeration fluid, such as water, which circulates between the solar energy heat exchanger 8 containing zeolite, and an evaporator 2 located in a cooling chamber 1 through a condenser 6, then return to the exchanger 8 through a three way valve 7. The device includes a second channel in the exchanger 8, which channel includes a fluid, and a second exchanger consisting of a tube with fins 20 connected to a storage tank 25 containing water at various temperatures. During the day whenever the period of sunshine is not sufficient, additional heat in the form of hot water is provided to the exchanger 8.Conversely if the night temperature is not low enough, cooling in the exchanger 8 is assisted by a cooling device 23 located in the second channel. Hot water 25.degree. C. is provided by the excess heat produced by the sun at day's end.

Abstract: In accordance with the invention, the motor includes: a rotor component composed of a shaft (1) of magnetic material provided with regularly spaced projections (3), and a stator component comprising at least three multipolar stators encircling the shaft consecutively, each polar core having cavities on the shaft side so as to constitute projections (13) of the same width and spacing as those of the shaft, with the spacing between stators being such that the projections of the shaft and those of the polar cores face one another for only one of the stators. A tight casing (2) is arranged to intersect the stator magnetic circuit and magnetic parts (21) extend the polar core to the interior of the casing. Application to nuclear reactors.

Abstract: Apparatus for controlling a nuclear reactor by vertical displacement of a unit absorbing neutrons, comprising, inside a sealed enclosure (1) in communication with the interior of the reactor, a movable magnetic piece (6) connected to a control shaft (3) which is itself connected to the absorbent unit. This magnetic piece (6) has at least two radial projections (7). The magnetic piece (6) is displaced by an inductor (10) with at least two pole shoes (16) corresponding to the projections (7) on the magnetic piece (6) and allowing magnetic coupling between the inductor (10) and the magnetic piece (6). The inductor (10) and its displacement device (30, 32, 33) are disposed outside the sealed enclosure (1). A control means (38) allows the control shaft (3) to be uncoupled from a member (36, 37) assuring its suspension so as to drop the absorbent unit in the event of emergency shutdown. The apparatus is particularly applicable to control rods of pressurized water nuclear reactors.

Abstract: The invention concerns the transformation of alternating or direct current input power to alternating current output power with intermediary transformation in direct current by means of static converters.According to the invention, an adapter placed in the direct current intermediary circuit (4) comprises a branch connected between the output terminals of the input converter (5), and contains in series a free wheel thyristor (18) and an inductance (16) whose value is equal to the total loss inductance of the motor (1) connected to the reversible output inverter (20).The purpose is to reduce the current wave harmonics in the power supply.

Abstract: An adjustable current input inverter-induction motor drive using a commutation bridge associated with a common commutating capacitor and four commutating thyristors. Capacitive means is provided for transferring energy during commutation from one main thyristor branch to the next in sequence through the inverter, and a capacitor inputting in a transformer and full wave rectifier bridge is provided coupled to said capacitive means for recuperating excess energy and for restitution thereof into the DC link of the inverter.