Showing papers on "Inert gas published in 1974"

Alkali metal leak detection method and apparatus

Abstract: A method and apparatus for detecting a leak of an alkali metal in liquid form in a structure such as the heat transfer system of a nuclear reactor. When alkali metal leaks from its containment structure and thereupon comes into contact with a compound containing hydrogen which can be displaced by the alkali metal, a chemical reaction occurs by which hydrogen gas is generated. The hydrogen gas so generated will diffuse very rapidly throughout the region proximate to the sodium leak. The hydrogen compound can be present in a variety of physical forms. The compound barium hydroxide is especially suitable as a source for the generation of hydrogen gas. Water vapor in air or in an inert gas also provides a suitable hydrogen source. A sensor located within the region of the alkali metal leak will sense the presence of hydrogen gas and will thereupon activate an alarm or recording device. The efficiency of the leak detection system can be evaluated and periodically tested by simply introducing a measured quantity of hydrogen gas into the region proximate to the alkali containment structure. This obviates the necessity of effecting a controlled alkali metal leak in order to test the leak detection system.

Cyclohexane oxidation in the presence of binary catalysts

Abstract: The process of oxidizing cyclohexane to produce cyclohexanone and cyclohexanol in the weight ratio of 0.5 to 1.5 of cyclohexanone to cyclohexanol, said process comprising contacting a stream of liquid cyclohexane with oxygen in each of at least three successive oxidation stages by introducing into each stage a mixture of gases comprising molecular oxygen and inert gas, said oxygen being introduced in amounts that may range from an amount that will substantially all react with the cyclohexane under the particular conditions involved to an amount in excess of the amount required to react with the cyclohexane, said excess being such that the overall oxygen consumed in the oxidation zone is not more than 95 mole percent of the amount fed under the particular conditions involved, in the presence of a binary catalyst system comprising 0.02 to 0.9 ppm chromium and 0.1 to 5 ppm cobalt at a temperature of from 130° to 200° C. and a pressure of from 60 to 350 psig, reacting any cyclohexylhydroperoxide that may be formed in the presence of said binary catalyst system and recovering a product of cyclohexanone and cyclohexanol in the above ratio.

Viscosities of binary gas mixtures at high temperatures

Abstract: The viscosities of He + Ar, Ar + Kr and CH4+ CF4 binary gas mixtures have been measured over the temperature range 293–1600 K using a capillary flow technique. The results are in good agreement with existing data both for the pure components (up to 1600 K) and for the inert gas mixtures (up to 1000 K). They have been analyzed in terms of the so-called interaction viscosity, η12, which is characteristic of the unlike pair interactions and essentially independent of composition. The application of this quantity of the estimation of other transport properties for gas mixtures and to the direct determination of pair potential energy functions for unlike molecules is discussed.

Some aspects of splat-quenching in an inert atmosphere and of the formation of non-crystalline phases in Al-17.3 at. % Cu, germanium and tellurium

Abstract: An apparatus for splat-quenching by the gun technique in a sealed, inert atmosphere is described. The importance of a low-oxygen quenching atmosphere in promoting efficient spreading of liquid particles and good thermal contact with the quenching surface is shown. A cooling rate of ∼1010 K sec−1 was estimated from the interlamellar spacing in a quenched Al-17.3 at. % Cu alloy. The process mechanisms of the gun technique are discussed with particular reference to the atomized droplet size and the effective specimen thickness for heat transfer.

Chlorine regeneration of platinum group metal zeolite catalysts

Abstract: The regeneration of a Pt group metal-acid-resistant, alkali-metal deficient zeolite catalyst comprises (a) a burn off at 500° C max (b) a treatment with inert gas, 0.5-20% vol 0 2 and 5-500 ppm vol Cl at 400°-550° C (c) a purge and (d) a reduction in a stream of H 2 at 200°-600° C. The treatment with inert gas, 0 2 Cl is believed to redistribute the Pt group metal and restore catalyst activity in a way that burn-off alone cannot do. The Cl may be added as Cl, Cl,HCl or an organic chlorine-containing material. The catalysts may have a SiO 2 - Al 2 O 3 molar ratio of at least 5:1 to ensure acid resistance and the preferred catalyst is Pt-H-mordenite which has been used for the selective cracking of n-paraffins in petroleum fractions.

Level control of dry-jet wet spinning process

Abstract: In a process for forming fibers by extruding a spinning dope successively through a layer of inert gas and a tube immersed in a coagulating bath, the tension profile of the yarn passing through the tube is regulated by regulating the pressure of the layer inert gas. In this pressurized quench system, the coagulating liquid is maintained at a predetermined level, despite transient changes in liquid input, by passing both pressurized gas and coagulating liquid through a pipe having an opening at the level to be maintained.

Extruded tobacco sheet

Abstract: A method and apparatus for the preparation of controlled and reduced density reconstituted tobacco materials comprising injection of inert gas into a low moisture tobacco composition maintained at an elevated temperature and paste-like consistency. Preferably, the inert gas is heated to a temperature within about 40°C of the composition prior to injection, and extruder means comprising high and low pressure zones is employed, with the point of gas injection selected to lie within the low pressure zone of the extruder or at the inlet port of a gear pump positioned after the extruder. Reconstituted tobacco materials (usually of sheet configuration) produced are characterized by even texture, uniform appearance, steady burning, and desirable taste, and can be prepared at densities lower than natural leaf.

Electron microscopy of size distribution and growth of small zinc crystals formed by homogeneous nucleation in a flowing inert‐gas system

Abstract: Homogeneous nucleation of small Zn particles has been observed in a flowing inert‐gas system. Zn vapor was produced by heating the bulk metal near 700 K in flowing N2 at pressures near 15 Torr. Nucleation of small Zn particles took place in a cooler region downstream from the furnace. Cooling occurred by gas conduction to room‐temperature walls. Particle sizes measured by electron microscopy were from 5 to 5000 nm. Samples were obtained with varying metal temperature, gas flow rate, pressure, and position in the collection chamber. Particles grew with time and had a predominant shape characterized as a regular hexagonal prism.

Refueling equipment for aircraft fuel tanks and the like

Abstract: Refueling equipment for aircraft fuel tanks of the type which are pressurized during flight of the aircraft by an airborne source of inert gas such as nitrogen to maintain the ullage gases noncombustible characterized in that the fuel during the course of its flow through said refueling equipment is deoxygenated before it reaches the aircraft fuel tank with the oxygen liberated from the fuel being discharged from the refueling equipment. The fuel passing through the refueling equipment is deoxygenated by scrubbing with noncombustible ullage gas (fuel vapor, inert gas, and oxygen insufficient to support combustion) from the aircraft fuel tank or by scrubbing with inert gas such as nitrogen carried by said equipment via control means operative to minimize the inert gas flow according to the fuel flow rate through the equipment into the aircraft fuel tank, or by subjecting the fuel to partial vacuum while the fuel is agitated thus to liberate oxygen therefrom and to discharge the same from the refueling equipment.

Transfer line burner system using low oxygen content gas

Abstract: Carbonaceous solids are heated in a transfer line burner during coal gasification or a similar process by introducing a dense phase stream of the solids into the lower end of the burner in the presence of a substantially inert gas; injecting sufficient gas having a molecular oxygen content less than that of air, normally between about 1 and about 15% by volume, into the dense phase stream near the bottom of the burner to promote a transition from dense phase to dilute phase flow and initiate the combustion of carbon; and withdrawing flue gas and heated solids overhead from the burner. The use of a gas of relatively low molecular oxygen content alleviates ash fusion problems and related difficulties.

2'-Hydroxy-2'-desamino-4,6-di-O-(aminoglycosyl)-1,3-diaminocyclitols, methods for their manufacture, method for their use as antibacterial agents, and compositions useful therefor

Abstract: 5-Deoxy-4,6-di-O-(aminoglycosyl)-1,3-diaminocyclitols, useful antibacterial agents, are prepared by the reaction of the corresponding 5-O-thioformyl-4,6-di-O-(aminoglycosyl)-1,3-diaminocyclitol having all amino functions and all primary and secondary hydroxyl groups protected, with an organotin hydride (preferably tri-n-butylstannane) in an inert aprotic solvent under an inert atmosphere at temperatures of at least about 100° C, followed by removal of said hydroxyl and amino protecting groups

Process for preparing hydrophobic particles

Abstract: A process for preparing hydrophobic finely divided oxides of metals and/or oxides of silicon comprising activating finely divided particles of oxides of metals and/or oxides of silicon by heating the particles at about 700° - 1000°C for less than about 60 seconds in a stream of inert gas to substantially completely free the particles of not only the physically bonded, but also the chemically bonded water, and contacting the activated particles with at least one organosilicon compound and substantially anhydrous ammonia gas for less than about 60 seconds. The hydrophobic products are useful as fillers in elastomers.

Decarburization of stainless steel: Part I. A mathematical model for laboratory scale results

Abstract: A mathematical model is presented for describing the reaction of iron-chromium-carbon melts with pure oxygen, air and oxygen-argon mixtures. The model is based on the generalization of the Asai-Muchi model for oxygen steelmaking to systems containing chromium and where the oxygen blown is diluted by an inert gas. The predictions based on the model were compared to the experimental measurements of Barnhardt obtained with heats of about 1.2 to 1.5 kg, having carbon contents ranging from 0.3 to 0.6 wt pct and chromium contents of 0.0 to 21.0 wt pct. The agreement between measurements and predictions was quite good for a variety of blowing arrangements which included top blowing with pure oxygen or air and bottom blowing with air. The fact that this good agreement was obtained by using a single value of the adjustable parameter in the model for all runs, renders very promising the extension of the model to more complicated systems.

Method for producing isotropic pyrolisis carbon coatings

Abstract: A material having a vapor pressure of at least 5 mm Hg at 490°C. and selected from aromatic and cycloaliphatic hydrocarbons and alkyl derivatives thereof, nitrogen-, oxygen- and sulfur-containing compounds having hetero rings and alkyl derivatives thereof, substituted compounds of these compounds, and substances containing these compounds is used as starting material. Such starting material is brought into contact in a vapor state, if necessary, diluted with an inert gas, with a substrate heated at a temperature of 600°-1500°C. thereby depositing the resulting isotropic pyrolytic carbon on the substrate.

Process of preparing a secondary electron emissive coating on the interior walls of a microchannel plate

Abstract: A process of preparing a nickel secondary electron emissive conductive cong along the interior channel walls of a microchannel plate or by continuing the process of preparing a solid nickel conductor channel to provide a conductive panel and the apparatuses resulting therefrom. The microchannel plate is positioned in a heated oven, or deposition chamber, such that heated inert gases are forced through the open channels to stabilize the channel temperature. The temperature is then lowered and a nickel compound gas is mixed with the inert gas. The gas mixture is forced through the channels to decompose the microchannel plate material and deposit a thin nickel coating on the interior channel walls. If a conductive panel is desired, the process is continued until the entire channel is completely filled with nickel.

Arc welding torch

Abstract: An improved arc welding torch is provided wherein the welding torch comprises in combination a body portion having at one end an inlet for the introduction of inert gas; a head portion attached to the body portion at the end remote from the inlet for the introduction of inert gas and having at the opposite end an outlet for the discharge of inert gas, the head portion being in electrical contact with the body portion; a first conduit through the body portion for passage of the inert gas therethrough and a second conduit in the head portion for the passage of inert gas therethrough, the first and second conduits being in fluid communication; means for passing electric current through the body portion and head portion; and electrode means in electrical contact with the head portion, the improvement wherein the body portion includes a plurality of co-axial ball and socket joints and means associated with the same to maintain the ball and socket joints in any configuration to which the plurality of coaxial ball and socket joints are deformed. This allows the arc welding torch, and the electrode in particular to have access to portions of the workpiece which would be normally inaccessible.

Purification of Inert Gas

Abstract: The rate of removal of oxygen from inert gas by metallic getter is measured continuously, and the dilution model is adopted for explaining the rate of purification. The rate of removal of oxygen increases with flow rate. It is found that hydrogen and water vapor present in the inert gas contributes very effectively to reducing the oxygen partial pressure. The rate of removal of oxygen with a titanium getter increases with temperature below about 800°C, but levels off above about 800°C.

Process for the hydrochlorination of elemental silicon

Abstract: An improvement in a process for preparing silicon tetrachloride or silicon trichloride wherein elemental silicon is contacted with hydrogen chloride in a fluidized bed, the improvement residing in carrying out the process in the presence of an iron compound, which iron compound is present in an amount such that when calculated as iron, the iron content is 10 to 43 weight percent based on the weight of the total solids in the fluidized bed, at a temperature in the range of 260°-600° C, preferably in the absence of an inert gas

Inert gas permeation through homopolymer membranes

Abstract: New data are reported for the permeation of inert gases through polyethylene, polytetrafluoroethylene, and silicone and natural rubbers. Additional data are compiled from the literature. The relative solubilities of these gases are practically insensitive to chemical variations in the homopolymer. Hence variations in structure at the glass transition (Tg) and melting (Tm) temperatures that affect diffusion also unambiguously affect permcation. Consequently an equivalence results between permeation at a given temperature for different polymers and permeation at different temperatures for a given polymer. Although the diffusion coefficient changes continuously with temperature, the Arrhenius parameters Do and Ed apparently change discontinuously at Tg and Tm. Their magnitudes and variations with atomic weight reach maxima at about Tg. These data indicate a dependence of the classical correlation between Do and Ed on polymer properties. A perturbed diameter for the permeant, specific for each polymer, is proposed for correlating the Do and Ed data. This correlation makes the changes observed at Tg and Tm more perceptible.

Process for controlling rheology of c3+ polyolefins

Abstract: The rheology of C3 + polyolefins, eg polypropylene can be economically and conveniently controlled by injecting under pressure certain critical quantities of oxygen in an inert gas, eg, air into melted polymer as it is being processed within an extruder

Apparatus for the removal of after heat in a sodium-cooled fast reactor

Abstract: In a fast reactor in which each cooling loop comprises the primary sodium circuit which exchanges heat with the sodium of a secondary circuit by means of an intermediate heat exchanger, each cooling loop comprises in parallel with the secondary sodium circuit an auxiliary secondary circuit in which a chemically inert gas extracts heat from the primary sodium, said secondary auxiliary circuit being equipped with at least one gas turbine which is supplied with the inert gas and operates in a closed energy-producing gas cycle.

Method and apparatus for production of high quality powders

Abstract: An electric arc which is struck between an electrode and the surface of a pool of molten material rotates under the influence of a magnetic field to thereby free liquid particles from the surface of the pool. The particles produced are quenched in an adjacent inert atmosphere or solidified in a vacuum and become powder. This powder is then collected conveniently.

Method for treatment of molten steel in a ladle

Abstract: Treatment of molten steel in a ladle, which comprises blowing inert gas into the ladle from its bottom, partially immersing a receptacle which covers the portion of the molten steel where the inert gas bubbles out and maintain non-oxidizing atmospheres within the receptacle with the gas so as to prevent oxidation of the molten steel by the slag.