Abstract: Multilayer coating for polycarbonate substrate used as a glass substitute, consisting essentially of silica, oxygen and nitrogen, and hydrogen according to the formulaSiO.sub.2 :HSiN.sub.y :Hcharacterized by a composite structure of the coating combining an interferential system with a reflectance window extending over a narrow band of wavelengths from the lower edge of the visible region toward wavelengths shorter than ultraviolet on the one hand, and an absorptive system of which the band of wavelengths of transmission from the absorptive region to the transparent region is located in the reflectance window of the interferential system. There is thus provided a coating with an abrupt variation of coefficient of transmission. The multilayer coating is particularly useful as a glass substitute for automobile headlight lenses.

Abstract: The thermal treatment atmosphere is obtained by catalytic reaction of an impure mixture of nitrogen, advantageously obtained by permeation or adsorption, and hydrocarbon, the catalytic reaction being carried out at a temperature between 400.degree. and 900.degree. C., typically between 500.degree. and 800.degree. C., with a noble metal base catalyst, typically platinum or palladium on alumina support. The reaction may be carried out in a reactor placed inside or outside the furnace.

Abstract: The present invention provides an apparatus for performing a process for producing standard gas mixtures which entailspurifying a raw gas using a gas purifier (3) such as a known two stage gas purifier system, thereby generating a high-purity diluent gas;mixing the high diluent gas and at least one high-concentration standard gas, by generating a medium-concentration gas mixture; dividing the medium-concentration gas mixture into a first flow and a second flow;selectively mixing the first flow with a sample gas or a high-purity diluent gas or a mixture thereof, thereby obtaining a standard low-concentration gas mixture; andcontrolling the pressure of the sample gas, the second flow of the medium-concentration gas mixture and the standard low concentration gas mixture.

Abstract: Process and apparatus for preparing ultra-pure nitrogen containing less than 100 ppb (parts per billion) impurities, characterized in that at least the impurities consisting of carbon monoxide (CO) and/or hydrogen (H.sub.2) are removed by passing the gas from which at least one of these two components has to be removed, over a bed of particles including a metallic element namely copper (Cu) and/or ruthenium (Ru) and/or rhodium (Rh) and/or palladium (Pd) and/or osmium (Os) and/or iridium (Ir) and/or platinum (Pt) supported on a particulate support, by the technique of ion exchange and/or by the technique of impregnation. This technique enables to produce ultra-pure nitrogen by using it on air to be distilled as an additional step for the removal of CO.sub.2 and H.sub.2 O.

Abstract: The invention aims at preventing the risks of deformation and breaking down of the heat exchanger which is part of a plant for the batch treatment of fluids, of the type in which, during active periods which are separated from one another by rest periods, at least one refrigerating fluid is allowed to circulate in first ducts of the exchanger, from the cold end to the hot end of the latter, and at least one calorigenic fluid is circulated in second ducts of the exchanger, from the hot end to the cold end of the latter, characterized in that, during rest periods, heat is introduced at the hot end and cold is introduced at the cold end of the exchanger so as to maintain these two ends at temperatures which are relatively close to those corresponding to the active periods, at least one of these two inputs being supplied by means of a reserve fluid of the plant.

Abstract: A process is provided for preparing carbon-containing substantially oxide-free iron powders or iron-based powders or both wherein oxygen impurities from an iron powder are removed without substantial decarburization, by heating the iron powder or iron-based powders or both under a substantially pure hydrogen atmosphere from ambient temperatures to a first intermediate temperature in an enclosure, then replacing the substantially pure hydrogen atmosphere by a substantially pure nitrogen atmosphere in the enclosure and then heating the powder to a second temperature which is higher that the first intermediate temperature, then cooling down the powder under an inert atmosphere to at least a temperature where substantially no more oxidation of the powder occurs, then removing the powder from the enclosure, the first and second temperatures being sufficient to reduce substantially all oxide impurities in the powder without substantial decarburization.

Abstract: The adsorber of the type comprising annular superposed beds, contains in its upper zone, a device to maintain and compress the upper bed, a flexible impervious membrane which separates the lower bed from the upper bed in its intermediate zone, and a cylindrical wall defining an internal annular duct for the lower bed in its lower zone. Application for example to the production of oxygen.

Abstract: The invention pertains to an installation comprising a reforming reactor (12) supplied with a vaporized and superheated methanol-water mixture, a device for heating the liquid methanol-water mixture by heat exchange (5) with the reformed gaseous mixture (56), a device for vaporizing and superheating the heated mixture by heat exchange (23) with a heat-carrying fluid (51), a device for effecting the reaction of the vaporized methanol-water mixture by heat exchange (28-29) also with the heat-carrying fluid (31-32), a separator (75) for separating the water from the reformed mixture by cooling and partial condensation (61-63-64), and a device for producing pure hydrogen which also produces residual combustibles, and a device (15) for heating the heat-carrying fluid (31-32) by combustion (15), in particular of the residual combustibles.

Abstract: The container includes a shell defining an interior volume and including a main part, peripherally bound by a portion of a main partition and an end part defining a duct giving access to the interior volume, the transverse dimensions of the duct being smaller than those of the main part and being closable by a shutter, and a level detector typically of the capacitive type, permanently disposed in the shell on at least one zone of the portion of the main partition, and connected to an outside box for the treatment of a signal of the detector. Application for example to cryogenic containers.

Abstract: The present invention provides a method of forming a free standing shape made of a material containing refractory metal, which entails providing a mandrel in a CVD enclosure, injecting a refractory halide gas and a reducing gas in the enclosure, reacting the gases in the enclosure to generate a material containing refractory metal, growing a layer of the material containing refractory metal on the mandrel and removing the mandrel to obtain the free standing shape, wherein the reducing gases is a silicon hydride gas or a mixture thereof.

Abstract: Improvement to the process of elementary analysis of a specimen by high frequency inductively coupled plasma mass spectrometry, by means of an apparatus including a torch for producing plasma from a plasma producing medium and for injecting the specimen in this plasma and an interface for taking a sample in the specimen, comprising two consecutive conical members disposed along the same axis except that the conical members have angles with different apices and are each provided with an axial orifice enabling a fraction of the specimen to be analyzed to pass therethrough. According to the invention, a given quantity of a make-up gas is added to the specimen which is injected into the plasma, the make-up gas having a high heat producing power, so as to raise the temperature of the plasma for locally heating the sampling conical members thereby preventing the components of the specimen which are present in the plasma from depositing on the conical members.

Abstract: A basket for arranging individual boxes in a cryogenic bath, comprises a vertically elongated body (1) of substantially U-shaped transverse cross section having an open access face (6), a plurality of horizontal transverse dividers (8A, 8B) to support boxes (2), and manually actuable locks for locking the boxes in position in the basket. The locks (9) each comprises a principal portion (10) and an end portion (11) mounted pivotably about a substantially vertically axis on a lateral portion (3B) of the body (1). Each lock is displaceable elastically between a stable locking position in which the principal portion (10) extends across the access face (6), and a stable unlocking position freeing the access face. A cryogenic container (20) receives at least one such basket supported by hooking over a neck (24) of the container (20).

Abstract: This column, of the type having a cross-undulating lining, includes means for returning liquid to the vicinity of the edges of the lining and liquid and gas distribution means which contribute to decrease substantially the height of the column. Application to plants for separating gases from air.

Abstract: A method of adsorption separation of gases of the kind which regenerates the adsorbant by pressure viariation and used two adsorbers, wherein the recompression stage includes at least one recompression stage using the oxygen produced, and a final recompression stage up to the high point of the cycle pressure using air intake without draw-off; and wherein the pressure high-point of the cycle is selected between 1.2 and 2 .times.10.sup.5 Pa and the pressure low-point is selected between 0.3-0.7.times.10.sup.5 Pa, at least the final part of the desorption stage being carried out by pumping. The method is essentially relevant to the production of oxygen.

Abstract: The invention relates to a tundish for the continuous casting of steel having a housing for the injection of gas with a feed tube for gas, the injection housing having an upper wall which is permeable to the gas. Periodically, the injection housing is completely replaced by removing the sealing grout.

Abstract: The process comprises circulation in a vessel containing the germs during a time T.sub.1 a ternary gas mixture comprising about 5% carbon dioxide, between 3.5 and 5% hydrogen; the balance consisting of nitrogen, followed by sealingly closing the vessel containing this gas mixture, advantageously under a slight overpressure, these operations are carried out automatically by means of an assembly comprising a gas feeding line and a gas outlet line each provided with an electro-valve and being electronically controlled.

Abstract: To heat a thermic enclosure, flames are generated in a burner having a plurality of injectors, from an oxy-combustible mixture, the flames extending in different directions and having different power and/or oxidizing reducing capacity. Application for example to the heating of furnaces or metallurgical ladles or glassware furnaces.

Abstract: This process is of the alternating type. When the demand of oxygen is lower than the mean value, additional liquid oxygen is produced by introducing compressed oxygen, in gaseous form, in the heat exchange line of the arrangement, the flow of liquid nitrogen injected into the double column being reduced in a corresponding manner. It is thus possible to increase the average yield of the arrangement when extracting argon.

Abstract: Substantially all residual oxidizing gas in a treating atmosphere which is inert or reducing, is eliminated by injecting into the atmosphere a gaseous silicon hydride at a temperature between 50 and 1,600.degree. C. and in amount such that the ratio R of the content of hydride to the content of oxidizing gas to be eliminated is within the range of 1.5 to 20. The rapid action of the trace amounts of hydride injected enables one to control with precision heat treatment processes by maintaining the residual oxidizing gas contents below predetermined very low thresholds.

Abstract: The article of which the verticality is critical, for example a distillation column disposed in a closed envelope, is associated with an indicator of verticality comprising a suspended mass and a locating ring. The envelope, which contains the various inner articles, is placed on a base by means of supports and its inclination with respect to the base is adjusted by controlling the relative position of the mass with respect to the ring. Application for example to cold boxes for the in situ production of gas from air.