Showing papers on "Mixing (process engineering) published in 1993"

Apparatus for producing compound semiconductor devices

Abstract: An apparatus for producing a compound semiconductor layer includes a first flow rate controller for adjusting flow rates of respective material source gases, a gas mixing pipe for mixing the respective material source gases, gas distributing pipes for distributing gases and connected to the gas mixing pipe, a second flow rate controller for adjusting flow rates of the material source gases flowing through the gas distributing pipes and for supplying the material source gases to a reaction tube, a pressure detector for detecting pressure in the gas mixing pipe, and a third controller responsive to the pressure detector for controlling the second flow rate controller to maintain a constant pressure in the gas mixing pipe. Retardation of the gases between the first and second flow rate controllers is avoided, improving thickness uniformity in grown layers.

Bone cement mixing and loading apparatus

Abstract: An apparatus for mixing bone cement and containing the mixed bone cement preparatory to dispensing. The mixing chamber has an outlet for the mixed cement. A cartridge has an inlet releasably coupled to the outlet of the mixing chamber for receiving mixed bone cement therefrom. Structure is provided for moving cement from an upper region of the mixing chamber down into a lower region thereof to mix same and for moving such mixed cement off an inner surface of the mixing chamber and into the cartridge.

Micro mixer with fast diffusion

Abstract: A concept for micromixing of liquid is introduced, and its feasibility is demonstrated. The mixer allows fast mixing of small amounts of two liquids and is applicable to microliquid handling systems. The mixer has a channel for the liquid, an inlet port for the reagent, a 2.2-mm*2-mm*330- mu m mixing area, and 400 micronozzles (15 mu m*15 mu m) through with a reagent is injected into the sample liquid. The resulting microplumes greatly increase the contact surface between the two liquids and hasten the speed of the mixing by diffusion. The fabrication process is extremely simple. The mixing is complete within a few seconds; a homogeneous state of mixing is reached in 1.2 s when the total volume injected is 0.5 mu l and the injection flow rate is 0.75 mu l/s. >

Multi-station semiconductor processor with volatilization

Abstract: Disclosed are apparatuses and methods for improved processing of semiconductor wafers and the like using vapor phase processing chemicals, particularly aqueous hydrofluoric acid etchants. Homogeneous vapor mixtures are generated from homogeneous liquid mixtures. Means for recirculating, mixing and agitating the liquid phase reactants are provided. In some embodiments the liquid phase is advantageously circulated through a chemical trench within the processing bowl. Exposure of wafers to vapors from the chemical trench can be controlled by a vapor control valve which is advantageously the bottom of the processing chamber. The wafer is rotated or otherwise moved within the processing chamber to provide uniform dispersion of the homogeneous reactant vapors across the wafer surface and to facilitate vapor circulation to the processed surface. A radiative volatilization processor can be utilized to volatilize reaction by-products which form under some conditions. The apparatuses provide efficient uniform etching with low particle count performance.

Flexible, sterile container and method of making and using same

Abstract: A flexible, sterile container is provided for sterile storing and mixing of medicaments and liquids which includes a shell with at least one compartment. At least one sterile liquid-containing pouch is in one of the compartments, and a medicament is in the compartment with the pouch or is in a different compartment. The liquid and medicament are mixed together by squeezing the shell and pouch to rupture the pouch to release the liquid for mixing with the medicament just prior to dispensing the mixture.

Method and apparatus for metering and mixing non-compressible and compressible fluids

Abstract: The present invention is directed to methods and apparatus for effectively proportioning a mixture of compressible and non-compressible fluids, wherein the resulting mixture has an almost constant density. The present invention is particularly useful for admixing supercritical fluids with polymeric coating compositions for various spray applications.

Apparatus and method for continuously mixing fluids

Abstract: Apparatus and method of hydrating a particulated polymer and producing a well treatment gel includes a mixer for spraying the polymer with water at a substantially constant water velocity and at a substantially constant water spray pattern at all flow rates of the water. A centrifugal diffuser is connected to the mixer for receiving the mixture, centrifugally diffusing the motive energy of the mixture, and hydrating the mixture into a gel. A centrifugal separator and constant velocity jet pump may be connected between the mixer and the centrifugal diffuser. A dilution valve is connected to the discharge of the centrifugal diffuser for mixing water with the gel at a substantially constant mixing energy at all flow rates of the gel and producing a diluted gel. A viscometer may be connected to the discharge of the dilution valve for measuring the viscosity of the diluted gel and regulating the flow of gel from the centrifugal diffuser to the dilution valve in order to control the viscosity of the diluted gel.

Gravity feed fluid dispensing system

Abstract: A gravity based system for accurately dispensing a fluid and for mixing the fluid with another fluid. The system includes a bottle containing a quantity of the fluid. The bottle may be inverted and engaged with a dispenser assembly. The system is constructed so that the bottle is opened to allow the fluid to flow through the system when the bottle is engaged with the system, and to close the bottle when not engaged with the system. A second fluid may be introduced into the system and mixed with the first fluid in a controlled manner to dilute the first fluid.

Apparatus for dissolved air floatation and similar gas-liquid contacting operations

Abstract: An apparatus for dissolved air floatation (DAF) and for gas-liquid contacting operations by dissolved air floatation. A number of involute flow channels in a container have inlets and outlets positioned at either end for involutional or evolutional flow of a mixture of liquid and dissolved gas. Liquid turbulence and mixing are prevented in order to achieve a near plug-flow condition for maximum separation. Other uses of the method and apparatus include hydraulic flocculation of suspended matters in a liquid, separation of non-floatable suspended matters, oxidation of dissolved organic matter, activated sludge processes, purification of water using a biocide, separation by absorption of gases, stripping by desorption of dissolved gases, and gas-liquid reactions.

Process for uniformly moisturizing fumed silica

Abstract: An improved process for uniformly distributing high levels of water in hydrophilic fumed silica by mixing with dry water.

Process for the continuous production of a granular detergent

Abstract: A process for the continuous production of a granular detergent composition comprising: (a) pregranulating at least 40% by weight of a mixture of solid and liquid detergent components, based on the total weight of the solid and liquid cleaning components, in a first low-speed mixer/granulator having mixing tools contained therein, to form a pregranulated detergent mixture; and (b) granulating the pregranulated detergent mixture in a second high-speed mixer/granulator to form a final granular detergent composition.

Cement mixing and pumping system and method for oil/gas well

Abstract: A system and method for mixing cement slurries at an oil or gas well site and for pumping such slurries into the well provide automatic combined and interrelated density and pumping control and selectable sequential control of predetermined mixing and pumping stages. Specific conditions automatically controlled include water rate, water pressure, slurry density, recirculating slurry pressure and downhole pump rate. Each of these conditions is the subject of a respective control loop that operates independently, but under control from a central controller. The central controller generates interrelated inlet water, inlet dry cement and outlet downhole pumping control signals responsive to operated-entered desired operating characteristics.

Some Specific Aspects of Combustion in Supersonic H2-Air Laminar Mixing Layers

Abstract: Development of Scramjet engines requires a detailed knowledge of the coupling between supersonic flow and chemical kinetics of combustion. In this paper we consider a stationary uniform, laminar supersonic mixing layer of hydrogen and air and investigate some conditions under which ignition occurs. More specifically, the influences of viscous dissipation effects, initial temperature and/or velocity gradients are investigated. This problem, where detailed chemistry for H2-air is used, is solved numerically. The structure of the reactive mixing layer is shown to consist of an induction region, a thermal runawayregion, a region where both premixed and diffusion flames coexist, and a pure diffusion flame region. The exact length of the induction zone is found to depend sharply on the upstream boundary conditions and more precisely on the intensity of viscous dissipation together with amplitude and direction of transverse temperature and velocity gradients.

System for mixing and activating polymers

Abstract: An apparatus for mixing and activating polymer which includes the introduction of gas with water and polymer in order to create a variable density type foam which aids in the activation and enhances the efficiency of the polymer. The apparatus of the preferred embodiment provides the introduction of water and polymer into a mixing loop having a premixing manifold containing a static mixer, injecting or sparging gas into the outflow from the static mixer, blending and activating by mechanical agitation the water polymer and gas mixture, partially feeding back into the mixing loop the mixture to provide a desired level of polymer activation which is delivered at a desired rate of flow. This system provides capabilities for selecting the desired level of activation, levels of polymer concentration, levels of overall flow rate as well as controlling the various energy imparting elements of the apparatus.

Enhanced gas-liquid mixing under variable liquid operating level conditions

Abstract: A gas-liquid mixing system employs an impeller/draft tube (8) assembly submerged in liquid. Hollow eductor tubes (10-11) affixed to the impeller drive shaft are used to flow gas from an overhead gas space to the liquid in the vicinity of the assembly. The positioning and size of the eductor tubes are such as to maximize the desired gas-liquid mixing and reaction rate.

Mixing and aluminum precipitation

Abstract: Aluminum hydrolysis in mixed liquid reactors is a problem with multiple kinetic and mixing time scales. Since some of these times scales overlap, and since aluminum hydrolysis has multiple pathways (some of which are slowly reversed), we have modeled aluminum precipitation as a coupled mixing and chemistry problem. For the base neutralization of dilute aluminum chloride in a standard stirred reactor with Rushton impeller, mixing submodels are combined with simplified aluminum chemistry models to predict the effect of mixing on steady-state pH at various formation or neutralization ratios

The assessment of dispersion of fine ceramic powders for injection moulding and related processes

Abstract: A method for the assessment of dispersion of fine ceramic powders in an organic vehicle for use in injection moulding and related processes is described. The procedure combines the quantitative evaluation of maximum shear stress in twin-roll mixing with the examination of agglomerate breakdown by scanning electron microscopy using the back-scattered electron image technique. The effect of shear stress, mixing time and the strength of agglomerates on the dispersive mixing process was investigated. Two-spray-dried ZrO2 powders and one TiO2 powder were examined by mixing with a polystyrene vehicle. The results suggest that the maximum shear stress during mixing should be five to 10 times greater than the agglomerate strength in order to disperse the powder in an organic vehicle. Mixing time was found to be less important. The microscopical technique can be used on its own to examine the state of dispersion of powders in organic materials after dilution in the mixing device.

Gas turbine apparatus including fuel and air mixer

Abstract: A fuel and air mixing apparatus for a combustor and gas turbine generator A primary portion of the fuel is injected into the mixing air at long distances from the combustor prechamber The primary portion of the fuel is almost completely mixed with the mixing air A secondary portion of fuel is injected into the mixing air in the boundary layer at a short distance form the combustor prechamber This minimally mixed second portion provides some rich portions of fuel-air in the prechamber to improve stability and reduce the chances of blowout

Composition for bleaching humain hair and method of producing it

Abstract: A bleaching composition, which is in the form of a free-flowing powder, for human hair having improved use properties, especially freedom from dust and ease of mixing with aqueous hydrogen peroxide solution, is obtained by adding an oil or a liquid wax to a powder which contains at least one solid peroxy compound and at least one vehicle in the form of a powder, preferably by spraying on.

Steam extractor hood for cooking hob - has ventilation fan providing air curtain around hub surface to prevent mixing between steam and room air

Abstract: The extractor hood (10) has an extractor housing (12) containing an extractor fan at the rear of a suction surface (14) which is enclosed by a blast jet opening (20) over at least part of its periphery having a number of slit apertures coupled to a ventilation fan (21), for providing an air curtain (22) around the hob surface (4). Pref. the jet blast opening (20) is defined between the peripheral edge of the extractor housing and the inside face of a surrounding ventilation hood (25), with limited adjustment of the air flow direction at its exit. USE - For wall mounting.

Method for the preparation of powder mixtures

Abstract: A method for producing powder mixtures capable of inducing an even more intimate, microhomogeneous intermixing in a heterogeneous powder composed of at least two types of powders. The method is effective even for the mixing of an aggregable powder and a nonaggregable powder. According to the method, a heterogeneous powder composed of at least two type of powders that have been preliminarily mixed by stirring is introduced into an inlet while a rotating axle is turning and is axially transported within a cylinder by a screw. As the heterogeneous powder passes between rotating disks and fixed disks, it is subjected to a highly efficient mixing by compression and shear forces due to a sliding-shear action exerted between depressions and elevations installed on the opposing surfaces of the rotating disks and fixed disks. The mixture passes in sequence through multiple stages of the rotating and fixed disks. A powder mixture, which has been microhomogeneously interdispersed, is discharged from the outlet.

Corresponding-States Model for Viscosity of Liquids and Liquid Mixtures

Abstract: A corresponding-states viscosity model using oxygen, octane and water as the reference fluids was developed for a variety of liquids and liquid mixtures. The present model is generally accurate for most pure liquids being tested. A set of quadratic mixing rules is adequate to correlate the viscosity of non-aqueous solutions. Using an augmented asymmetric mixing rule to calculate the pseudo-critical temperature yields a good representation for the binary and ternary aqueous solutions

Process and apparatus for precise volumetric diluting/mixing of chemicals

Abstract: Apparatus and method for accurate measuring and mixing of chemicals is disclosed. The apparatus includes one or more metered vessels having a container of predetermined volume and at least one constricted vent tube therein. By mounting a sensor on the constricted vent tube, a greatly amplified measurement of the precise chemical volume in the metered vessel is provided. The apparatus and method of the present invention readily lends itself to a variety of applications and can be adapted to handle virtually any form of chemical mixing, diluting, or generating process.

FCC riser cracking with vortex catalyst/oil mixing

Abstract: A process and apparatus for mixing feed and catalyst in the base of a fluidized catalytic cracking (FCC) reactor are disclosed. Regenerated catalyst flows through an annular region into a deceleration zone of increased cross-sectional area which induces vortices of circulating catalyst. Liquid feed is injected into the vortices, preferably via radially distributed feed outlets on a centrally mounted, truncated cone injector support means having a vortex convergence prevention means just above the feed outlets. Preferably catalyst and feed accelerate from the mixing device into the base of a riser reactor.