Abstract: A process and an installation for the production of a variable flow rate of at least,one principal constituent of air under pressure, wherein a constituent is withdrawn in liquid phase from an air distillation apparatus (12), this liquid is brought to a vaporization pressure, and the liquid is vaporized under this vaporization pressure by heat exchange (in 9) with a calorific fluid under high pressure. The flow rate of the constituent is adjusted by modifying the flow rate of the liquid to be vaporized and the vaporization pressure. The vaporization pressure is intermediate the withdrawal pressure and the production pressure. The gas resulting from the vaporization is compressed in a compressor (20) to the production pressure.

Abstract: The content of peracid, in the presence of hydrogen peroxide,in a solution 2 in which the molar ratio between the concentration of hydrogen peroxide and the concentration of peracid is not higher than 100, is adjusted by means of a process according to which the solution is drawn by a pump 3 into the suction circuits of two pumps 5, 6, which operate at the same flow rate and may draw simultaneously a dilution and /or pH control liquid 9. Pump 5 feeds the reference vat 7 of a two-beam photometer and pump 6 feeds the measuring vat 8, and the flow rates of the pumps 3, 5 and 6 are adjusted so that the concentration of peracid in the measuring flow 10 is lower than about 100 ppm by weight. An excess of iodide 11 is added to the measuring flow 10 which exits from the pump 6 by a pump 13 and measuring unit 14, to which are connected the cells of the photometer.

Abstract: A process for converting a copper or nickel matte comprising at least 30% by weight of a copper or nickel based material and a substantial weight amount of an iron based material as one of the impurities to be removed from the matte by oxidation in a converter wherein during a first step of said process substantially all of the iron based material is oxidized with an oxygen comprising gas to make ferrous oxide which is thereafter transformed into slag by addition of a solid material to the molten metal and during a second step of said process, the copper based material is oxidized with said oxygen comprising gas to generate substantially pure copper and residues, said residues being essentially in gaseous form, the oxygen comprising gas being injected through an internal injector of a concentric shrouded tuyere comprising the internal injector and an external injector concentrically disposed around said internal injector with a gas passage therebetween, a shrouding substantially inert gas being injected throu

Abstract: In a method of dry process fluxing at least one surface of a metallic article, the surface to be fluxed is treated with a plasma at atmospheric pressure of a gaseous mixture comprising hydrogen and optionally at least one inert gas. The invention also concerns an apparatus, particularly for practicing the process, as well as a process for soldering or plating.

Abstract: Process and installation for supplying at least one pure active gas to at least one utilization station (P.sub.i) in a first building (A) at a utilization site. It comprises the steps of providing, at the utilization site, a second safety building (B) at a distance from the first building (A), providing at least one source (2; 7; 10) of said gas in the second building (B), and transferring, by at least one safety conduit (C) of high cleanliness, the gas, at a low pressure, to the utilization station (P.sub.i). There is also taught the step of purifying (4; 11) the gas in the second building (B) before transfer to the conduit (C). The pure gas is prepared in situ (2, 4; 10, 11) in the second building (B). There can alternatively be provided, adjacent to the second building (B), at least one source of vector gas (1), with mixing in controlled fashion (6; 9), in the second building (B), the pure active gas with the vector gas before transfer of the mixture to the conduit (C).

Abstract: A method for the synthesis of cyclic polyamines preceeds by reaction of a diamine with the acrylonitrile wherein the reduction steps are carried out with Raney alloy instead of using hydrogen under pressure in the presence of Raney nickel. Compounds so prepared have the formula: ##STR1## wherein A and B are: an alkyl chain --(CH.sub.2)-- in which x is an integer of 2 to 4, substituted or not by an alkyl group of 1 to 5 carbon atoms, which may be substituted or not by an aromatic ring, heterocyclic ring, amine ketone, carboxylic acid, amide, cyano, alkyl, alkoxy, hydroxy, nitro or halogen and R.sub.1 and R.sub.2 are the same moieties as those substituting the alkyl claim above.

Abstract: A solder composition is applied to the pins of an electronic component. The pins of the component are brought into contact with solder at a soldering station having a bath exposed to a controlled atmosphere of low oxygen content maintained in a hood enclosing at least the surface of the bath. The controlled atmosphere is comprised of at least one neutral gas and a gaseous silicon hydride whose content is between 50.times.10.sup.-6 and 2.times.10.sup.-3 of the volume of the controlled atmosphere. The controlled atmosphere is produced:a) by introducing into the hood the neutral gas to bring the residual oxygen content to less than 200 ppm, thenb) by introducing into the hood the neutral gas and the silicon hydride with a content greater than four times the residual oxygen content in the controlled atmosphere, at the end of step a).

Abstract: There is formed a silicon-base antimigration barrier layer by projection, on a hot surface of a glass object, in an unconfined ambient atmosphere from a gaseous mixture comprising neutral gas, a silicon precursor, typically a silane, between 10 and 60% of ammonia and preferably less than 5% oxygen, the ratio of the oxygen and silane contents being comprised between 0 and 4. It is useful particularly for the treatment of sodium-calcium glass receptacles to prevent migration of ions into liquids contained in the receptacles.

Abstract: Process for improving a controlled oxidation reaction between at least one reactant and oxygen, in which at least one reactant is reacted with oxygen or an oxygen containing gas, constituting a reaction mixture, in the presence of at least one additional gas which is introduced into said reaction mixture and is selected from methane, ethane and helium, and the resulting reaction product from the oxidation reaction is possibly treated so as to give a final product.

Abstract: A separation of gas by permeation, comprising the steps of and the apparatus for compressing a gaseous mixture to be separated at a first temperature (Ta) in a compressor (2), cooling to a second temperature (To) the compressed mixture to condense condensable impurities in the compressed gaseous mixture, purifying the compressed gaseous mixture of condensable and/or adsorbable impurities at a third temperature (T.sub.1) greater than the second temperature (T.sub.0) and passing the purified gaseous mixture into a gaseous permeation unit comprising at least one membrane module to obtain at least one production gas. The third temperature (T.sub.1) is so regulated that it will not be less than a first predetermined value. The second temperature (To) is greater than the first temperature (Ta) by a value comprised between 1.degree. and 5.degree. C., the first value being not less than 20.degree. C.

Abstract: Process and installation for the production of gaseous oxygen and/or gaseous nitrogen under pressure and of at least one liquid product by an installation comprising a single air distillation column (9) provided with a nitrogen refrigeration cycle. The air to be treated is compressed (in 1) to a first pressure at least equal to the pressure of the single column. At least a portion of the air is further compressed (in 4; 4, 4A) to a high pressure substantially greater than the pressure of the single column. A fraction of this air is condensed (in 7) by vaporization of liquid oxygen and/or liquid nitrogen withdrawn from the base of the column and pumped (in 14, 15) to the corresponding vaporization pressure. The gaseous oxygen and/or gaseous nitrogen is recovered (in 30, 28) under the resulting pressure, as product. The air thus condensed is subcooled (in 11), expanded to about the pressure of the column (in 20, 21), and introduced at least in part into an intermediate level of the column.

Abstract: Device for freezing products, comprising a vibrating trough (2) comprising a bottom wall (3) on which the products (9) to be frozen move in contact with a layer of liquefied gas (7). The bottom wall (3) has a pattern of alternating projecting and hollow parts. The projecting parts are distributed in a regular pattern and are in continuous registry with the hollow parts. The height (h) of the projecting parts does not exceed half the thickness (e) of the layer of liquefied gas. The projecting parts have a constant height (h). The bottom wall (3) is an embossed metal sheet, preferably of stainless steel.

Abstract: A cap for a cylinder of gas comprising a lower portion (2) adapted to be mounted on a gas cylinder (3) and an upper portion (1) defining internally a space (20-19) protecting a gas distribution valve structure (4) secured to the cylinder. The lower portion (2) comprises a portion (8) that projects laterally relative to the cylinder and comprises a downwardly opening cut out (12) permitting the support by hooking of the cap/cylinder assembly on a structural support element. The projecting portion (8) has a transverse external profile which is flat or of large radius of curvature permitting supporting on a flat surface the cap/cylinder assembly. The upper portion (1) comprises a transverse handle (22) in substantially vertical alignment with the laterally projecting portion (8). The upper portion (1) comprises two lateral vertical ribs (23A, 23B) connecting the handle (22) to the projecting portion (8). The cap/cylinder assembly is useful particularly for medical oxygen.

Abstract: Method and its device for evaluating semiconductor wafers that evaluates semiconductor wafers by estimating the dopant level which is equivalent to the critical value at which the excess minority carrier injection density reaches the high injection state, and that measures the minority carrier lifetime at a low-injection-state exposure condition adapted to said dopant level. Excitation light (emitted by excitation light generator 4) is emitted onto a semiconductor wafer 2 at varying exposure conditions as imposed by an exposure condition controller 9. Detector 6 detects the change in the level of reflected radiation from microwaves emitted by microwave generator 5 onto the wafer 2. The dopant level in the semiconductor wafer 2 is estimated by estimation circuit 10' based on the change in the exposure conditions and the change in the minority carrier lifetime as determined by the change in the microwave level.

Abstract: All the air to be distilled is compressed to a first high pressure and is thereafter separated into two portions. The first portion, representing at least 70% of the flow, is boosted to a second high pressure and cooled down in a heat exchanger to an intermediate temperature, where a part thereof is work expended to the mean pressure while the remainder is liquefied. The second portion is cooled and liquefied in the heat exchange line, into one or a plurality of flows at one or more pressures between the first and second high pressures.

Abstract: The invention relates to a process for the electrolytic generation of arsine from an electrochemical cell provided with a cathode supplied with H.sup.+ and AsO.sub.2.sup.- ions where two concurrent reactions take place producing arsine and gaseous hydrogen respectively, and an anode where a reaction producing H.sup.+ ions takes place, the ratio of the H.sup.+ /As concentrations at the cathode being controlled and kept constant.

Abstract: Process and device for freezing substances contained in a receptacle, in which the receptacle (4) is placed on a support (7) and is moved along the support in a path. The support is a conveyor, preferably a vibratory conveyor, and is maintained partially immersed in a liquefied gas (13). The level of the liquefied gas (13) does not exceed the height of the substance in the receptacle (4). The vibratory conveyor comprises a vibrating trough (1) having two opposed walls (9) defining between them a guide channel (3) for the receptacles (4) and, on opposite sides, a chamber (10) for distribution of liquefied gas. A device (11) provides liquefied gas to each chamber (10). The bottom (7) of the vibrating trough (1) is of embossed sheet metal.

Abstract: A flow of air which has been compressed cooled dried is treated in a unit for separation by cryogenic distillation to give a flow of nitrogen; the oxygen enriched residual gases are, in part, sent at the inlet of a unit for separation by adsorption in which the outlet substantially produces oxygen. If the flow of oxygen is insufficient, additional air is injected. If the flow of oxygen is too important, an excess flow of residual gases is withdrawn. This apparatus enables to provide, at a lesser cost, independent flows of nitrogen and oxygen which are adjustable at will.

Abstract: A device for recycling a cryogenic liquid in a circuit (1) comprising at least one section (2) substantially at ambient pressure, the device comprising: a) a first cryogenic reservoir (4) to recover the liquid at the outlet of the section, this reservoir being provided with structure (4.sub.3, 6.sub.1, 7.sub.1, 8.sub.1) to pressurize the recovered liquid, b) a second cryogenic reservoir (5) continuously pressurized in operation and connected to the circuit (1) upstream of the section (2) open to the air to supply it with pressurized cryogenic liquid, the second reservoir being in selective fluid communication (16) with the first reservoir, and c) a device (12) responsive to a predetermined relationship of the levels of filling of the two reservoirs selectively to actuate the pressurization structure (4.sub.3, 6.sub.1, 7.sub.1, 8.sub.1) of the first reservoir (4) so as to transfer into the second reservoir (5) cryogenic liquid contained in the first reservoir.

Abstract: Process and installation for the production of gaseous oxygen and/or gaseous nitrogen under pressure, of the type in which air is distilled in a double distillation column (11) comprising a low pressure column (13) operating under a so-called low pressure, and a medium pressure column (12) operating under a so-called medium pressure. All the air to be distilled is compressed (in 1, 3, 7)to at least one high air pressure substantially greater than the medium pressure, and the compressed air is cooled to an intermediate temperature, and a portion of it is expanded in a turbine (8) to the medium pressure, before introducing it into the medium pressure column (12). The air which has not been expanded is liquefied, then introduced after expansion (in 20, 21), into the double column. At least one liquid product withdrawn from the double column is brought to the production pressure, and this liquid product is vaporized by heat exchange with at least one portion of the air to be distilled in the course of cooling.