Abstract: A process for the vitrification of products in the form of solid pieces or particles without the release of dust as a pollutant, according to which there is used a furnace (3) provided with a burner (15). There are introduced into the furnace the products to be vitrified, and the products are permitted to heat in the furnace until they form a liquid or pasty vitreous mass, then this vitreous mass is removed from the furnace and permitted to cool. The internal walls of the furnace are preheated with the burner to a temperature exceeding the temperature at which the products to be vitrified can form a liquid or pasty vitreous mass, then the energy supplied by the burner is reduced substantially or even cut off, before introducing waste into the furnace.

Abstract: In a "vacuum" type cycle, the depressurization of a first adsorber at the high pressure of the cycle is effected by placing it in communication with the outlet of a second adsorber at the low pressure of the cycle. This communication takes place simultaneously with countercurrent pumping in a first stage for the second adsorber and in a second stage for the first adsorber, the recompression to the high pressure of the cycle being effected by production gas. Used for the production of oxygen from air.

Abstract: A subassembly constituted by a body and a cover (2), defines internally gas conduit portions (I.sub.i) delimited by partitions of the body coacting with sealing strips (12) in grooves (11) of the cover (2) and formed and mounted in these grooves by injection molding. The sealing strips (12) are recessed within the grooves (11) and coact with the ends of the partitions of the body extending partially into the grooves (11). For use particularly in anesthetic apparatus.

Abstract: An air separating unit which can jointly produce high purity nitrogen gas and compressed dry air of high quality freed of hydrocarbons such as methane and ethane. The air separating unit is constructed such that compressed dry air freed of hydrogen, carbon monoxide, carbon dioxide and moisture is cooled down near to its liquefying point and introduced into a rectification column (30) and nitrogen gas separated by rectification from the compressed dry air in this rectification column (30) is taken out as a product. The rectifying portion in the rectification column (30) is divided into a lower rectifying portion (34) and an upper rectifying portion (36), and in this lower rectifying portion (34), hydrocarbons such as methane are mainly removed from the compressed dry air, and the compressed dry air which has passed through the lower rectifying portion (34) is taken out as a product.

Abstract: A method is provided for heating a gas in a regenerator with a heat accumulation mass consisting of a loose bulk material arranged in a ring between two coaxial cylindrical grids, a hot collection chamber, surrounded by the inner hot grid, for the hot gases and a cold collection chamber, enclosed between the outer cold grid, on the one hand, and the wall of the regenerator, on the other hand, for the cold gases, wherein the increase in the head loss during the heating phase is at least 5 times as great as the product .rho..g.H, in which H is the height of the regenerator, .rho. is the density of the gas at a temperature of 20.degree. C. and g is the acceleration due to gravity, and the gas flow rate is at least equal to 300 m.sup.3 N/h.m.sup.2 of surface area of the hot grid at standard pressure.

Abstract: The oxygen/fuel burner contains at least one first tubular component (2) conveying the oxidant and at least one second tubular component (3), for injecting the fuel into the oxidant flow,arrangd asymmetrically with respect to the first (2) so that the mixing region upstream of the flame contains a part where the ratio of the oxidant to the fuel is less than the soichiometric value.

Abstract: A solution of hydride in liquid nitrogen, the hydride being one that is in gaseous phase at atmospheric pressure and ambient temperature. The concentration of hydride in the liquid nitrogen is comprised between 0.05 and 10 mol %, preferably between 0.05 and 2 mol %, and more preferably between 0.1 and 0.3 mol %. The hydride is selected from the group consisting of arsine, germane, phosphine (PH.sub.3), diborane and silane (SiH.sub.4) and is preferably silane. Atmospheres prepared from these solutions are useful in the thermal treatment of metals, or for surface treatment, particularly of polymeric or metallic surfaces.

Abstract: Process and apparatus for the separation of at least one gas from an entering gaseous mixture (1), of the type in which a membrane separation is conducted with at least two successive membrane separators in the following manner: the entering mixture is passed through a first membrane separator (2) operating at a first operating temperature and all or a portion of the residual mixture (5) from this first membrane separator is passed through a second membrane separator (3) operating at a second operating temperature. A mixture enriched in the gas is obtained from the permeate outlet (6, 4) of each of these two separators. Two separators are used whose selectivities for the gas are different. These may be membranes of different type, or membranes of the same type, if the first operating temperature is different from the second operating temperature.

Abstract: The combined installation comprises at least one metal production unit (II), including at least one, and typically a series of metal production or treatment units (1-6), and at least one air gas separation unit (III) including at least one outlet for at least one air gas (14-18), the units being supplied with compressed air with a low water vapor content by a common compressed air production unit (I), and with at least one of the gas outlets (14-18) from the separation unit (III) connected to at least one of the devices (1-6) of the production unit, to supply the latter with gas.

Abstract: Liquid waste material, particularly material containing sulfuric acid, may be combusted using an oxygen-rich material by a process in which:(i) a primary oxidant and fuel issuing from a burner are combusted in a furnace, the proportion of primary oxidant to fuel being such that there is insufficient oxygen to combust the fuel completely;(ii) introducing into the furnace the liquid waste material in atomized form around the burner;(iii) introducing into the furnace spaced from the burner a secondary oxidant which contains sufficient oxygen to combust completely the fuel not combusted by the primary oxidant the direction in which each of the primary oxidant, fuel and liquid waste material is introduced being such that the substances flow in substantially the same direction, the rate at which the primary oxidant, fuel, liquid waste material and secondary oxidant are introduced being such that a plug flow of substances through the furnace is created.

Abstract: Provided herewith is a process for reducing the fluorescence of pulp fibers. The process comprises contacting the pulp fibers with ozone in two or more stages, with an intermediate washing stage or bleaching stage preferably being conducted in between the ozone contacting stages. It has been discovered that splitting the total ozone charge into two or more stages provides a much more efficient and effective process for reducing fluorescence.

Abstract: A process for treating a gaseous mixture, particularly air, by pressure swing adsorption (PSA), of the type in which three adsorbers (1 to 3) are used in each of which is carried out, for a given nominal production, a cycle comprising the following successive stages, the cycle being offset from one adsorber to the other by a third of the nominal duration (T) of the cycle:(a) a substantially isobaric adsorption phase at a high pressure (PM) of the cycle, by circulation of the mixture through the adsorber in a so-called co-current direction;(b) a desorption phase comprising a stage (b2) of pumping to a low pressure (P.sub.m) of the cycle less than atmospheric pressure, via a vacuum pump (7) of constant speed and continuous operation whose output is in the vicinity of atmospheric pressure; and(c) a repressurization phase of the adsorber to the high pressure of the cycle. During a reduction of the production flow rate, the mean intake pressure of the vacuum pump is raised for the duration of the cycle.

Abstract: A pressure swing adsorption unit comprises at least two absorbers, each absorber having at least a port connectable to at least one pumping unit. The pumping unit includes a first pumping stage and a second pumping stage. Each of the pumping stages are capable of discharging into an outlet conduit. A circuit is provided for selectively and alternately connecting a port to a source of feed gas and to the pumping unit such that the first and second pumping stages are sequentially fluidly connected in parallel, and then in series to reduce the pressure at the port to an intermediate vacuum level, and then to a low vacuum level.

Abstract: The invention concerns a process for depositing a thin layer of silicon oxide bonded to a substrate of a polymeric material comprising, concomitantly or consecutively (1) subjecting a surface of the substrate to an electrical discharge with dielectric barrier and (2) exposing said surface of the substrate to an atmosphere containing a silane, thus forming a deposit of silicon oxide bonded to said surface of the substrate Application to the production of sheets or films useful for example as food wrapping.

Abstract: In a process for the production of gaseous oxygen under pressure at a variable flow rate, of the type in which air is distilled in an air distillation installation comprising a distillation apparatus (7) and a heat exchange line (6) to cool the air by heat exchange with the products from the distillation apparatus; liquid oxygen is withdrawn from this apparatus, brought to a vaporization pressure, vaporized and reheated under this pressure in the heat exchange line, this vaporization and this reheating being accompanied by a liquefaction of air in the air liquefaction passages (21; 21,21A) of the heat exchange line.

Abstract: A process for producing a silicon oxide deposit at the surface of a metallic substrate comprising the following steps performed either concomitantly or successively: (1) treating the surface of the substrate with a corona discharge; and (2) exposing the surface to an atmosphere containing a silicon compound in the gaseous state. Both steps (1) and (2) are conducted at a pressure greater than 10,000 Pa. This process can be used to provide anti-corrosion treatment to a metallic substrate or to a metallized polymeric support.

Abstract: A high-speed jet of liquid oxygen (21) with a speed higher than 100 meters per second is delivered into the tuyeres of a blast furnace of cupola furnace together with pulverised carbon. The jet reaches the opposite wall of the cavity (9) formed at the outlet of the tuyere (6) in the mass of material contained in the shaft. Supplying oxygen to the bottom of the cavity improves the burning of the remaining coal, whereby higher injection levels may be achieved. The shape of the cavity may also be altered, and, in particular, faster reactions may be achieved in the axial region of the shaft.

Abstract: A process for combustion in an industrial furnace (1), using at least one burner (2; 3) supplied with combustible (4) and combustion supporting (5) fluids. The flow rate of at least one of the fluids is pulsed at a frequency comprised between 0.1 and 3 Hz. There is provided in the furnace (1) at least one pair of two burners (2A, 2B; 3A, 3B) disposed substantially confronting each other; and the fluid of the burners of a pair is pulsed in offset phase from one burner to the other. The frequency of pulsation is between 0.1 and 1 Hz. The flow rates of fluids are substantially identical for each burner (2A, 2B; 3A, 3B) of the pair. The power of the pair of burners is greater than 300 KW.

Abstract: In a pressure-swing adsorption-type gas separation unit, a distinct intermediate gas passageway is formed between a first water retaining bed (A) and a second separating adsorbent bed (B), a controlled heat flow being supplied to prevent the formation of a very cold area between both beds. The unit is particularly useful in the production of oxygen from air.

Abstract: The present invention relates to a wave soldering process wherein an inert gas atmosphere is injected inside the wave soldering machine, the inert gas atmosphere having a temperature which might be controlled. Particularly, the atmosphere can be heated at the same or different temperatures before injection, for example in the preheating zones, in the machine. The atmosphere can also be cooled (or injected at ambient temperature) e.g. in the cooling zone. Various atmospheres can be used (similar or different from one zone to another). Also, maintaining the atmosphere under forced laminer flow conditions improves the quality of the solder joints. The thermal efficiency of the heat transfer between the atmosphere and the printed circuit boards is thus greatly enhanced, which means less solder defects, higher components density and decrease of energy consumption and inert gas flow rate.