Abstract: A method for identifying an article provided with a coded magnetic member comprising creating a detection zone by supplying an exciter coil with exciting alternating current, passing the article with the coded magnetic member through the detection zone to produce at least one signal from the coded magnetic member and detecting the derived signal using a detector coil to determine the code of the magnetic member. The magnetic member is provided with at least one of a plurality of elements made of magnetic alloys each having a different hysteresis loop and a code value is assigned to each type of alloy. The code value of each of the elements is decoded by measuring the phase shift of the signal derived using the detector coil relative to the phase of the exciting alternating current. This phase shift is indicative of the type of alloy and of the code value assigned thereto.

Abstract: In the identification of an article provided with at least one identifying magnetic member, each identifying member is selected from one or more production batches each of which has a characteristic hysteresis loop which is virtually non-reproducible. The member is subjected to analysis of its magnetic characteristics which are compared with those of a reference magnetic means comprising the same number of magnetic members from the same batches as the identifying magnetic members. Identical characteristics provide a correct identification. The detection apparatus may comprise two exciter coils for providing two alternating magnetic fields and two detector coils for each field connected in opposition. When an identifying magnetic member inserted in one field is identical to the reference magnetic member inserted in the other field, detection signals from the two detector coils cancel each other out.

Abstract: An apparatus and process for identifying objects marked by a magnetic band or thin filament comprising detecting the passage of the magnetic band in a detection zone comprising a framework having an excitation coil fed with alternating current to produce an alternating magnetic field and a detecting coil balanced with the excitation coil such that no signal normally will appear in the absence of a magnetic body in proximity to the framework. The passage of an object carrying a magnetic band in proximity to the framework producing for each alternation of the excitation field an unbalance in a detecting circuit and the appearance of a signal which is fed to apparatus for the detection and measurement of the phase of the signal with respect to the excitation field.

Abstract: A conduit for conveyance of hot fluids includes an inner tube, through which the fluid passes, made of a material having a low coefficient of thermal expansion, preferably less than 5 .times. 10.sup.-6 per .degree. C and advantageously INVAR .RTM. with a coefficient of 2.3 .times. 10.sup.-6 /.degree. C. The inner tube is anchored at its ends and has no expansion-compensating means in its length is surrounded by a binding wrapping of a material having a coefficient of thermal expansion greater than that of the inner tube, prestressed at the temperature of application to compensate for the relaxation of stress in the wrapping due to the different expansions of inner tube and wrapping, and so as to compensate at least in part for changes in stress on the inner tube resulting from the absence of expansion-compensating means. A longitudinal tensile pre-stress may also be applied. The assembly also includes thermal insulation, disposed either outside the wrapping or between the wrapping and the inner tube.

Abstract: A cross bar switching matrix for electric conductors in two sets has a first array of strips of magnetic metal mounted parallel on an insulating support plate with laterally projecting tongues from each strip the ends lying freely on the support plate. A second set of metal strips identical to the first set but at right angles thereto is mounted on a second insulating support plate. The support plates are juxtaposed with the strips perpendicular to each other and the free ends of the tongues of each set are opposed and form with a portion of each of the associated strips a ring which is substantially closed but for a thin layer of electrically insulating material in the areas where the strips of each array cross those of the other. Electromagnetic control circuits made up of electric control conductors are associated with a respective one of the strips and each electric control conductor includes a conductor linked with each of the rings formed by the tongues of the respective array strip.