Showing papers on "Mixing (process engineering) published in 1988"

Sintered alumina-zirconia ceramic bodies

Abstract: Useful ceramic bodies can be made by mixing zirconia powder with seeded alumina gel, drying, and firing at a high enough temperature to convert the alumina in the gel to microcrystalline alpha alumina. Abrasive grits made in this way, with a zirconia content between 15 and 30 weight percent and at least half the zirconia in the tetragonal crystal form are particularly valuable for use in grinding wheels for snagging steels.

Methods of tar sand bitumen recovery

Abstract: Methods for the recovery of bitumen from tar sands comprising the steps of mixing tar sand, solvent and a displacing amount of aqueous medium to form a mixture, followed by separating a bitumen-rich solvent phase from the mixture and recovering bitumen from the bitumen-rich solvent phase are disclosed.

Gas-liquid mixing process and apparatus

Abstract: A high efficiency gas dissolution system is used to dissolve gas in a portion of a body of liquid, improving gas utilization and reducing associated energy requirements

Method and apparatus for foaming high viscosity polymer materials

Abstract: Polymer materials having viscosities ranging from about 50,000 up to above 1,000,000 centipoises are mixed with a gaseous foaming agent to provide a polymer/gas solution under pressure such that when the polymer/gas solution is subsequently dispensed at atmospheric pressure the gas is released from the solution and becomes entrapped in the polymeric material to form a homogeneous polymer foam. Mixing is accomplished by force feeding the gas and polymeric material into and through a low energy input disk mixer with a low pressure drop across the mixer such that premature foaming or reaction of the polymeric material is avoided. The disk mixer includes a tubular housing, one or more driven shafts extending along the length of the housing, and a series of disks spaced along the shafts. The foaming gas enters into solution in the polymer in the compartments between the rotating disks. The process is characterized in that relatively high viscosity polymeric materials are mixed with gas and foamed with relatively low horsepower requirements, high throughput and low temperature rise of the polymer from conversion of the work of mixing to heat.

Liquid phase mixing in mechanically agitated vessels

Abstract: Liquid phase mixing and power consumption have been studied in 0.3, 0.57, 1.0 and 1.5 m i.d. mechanically agitated contactors. Tap water was used as liquid phase. The impeller speed was varied in the range 2-13.33 r/s. Three types of impellers namely disc turbine (DT), pitched turbine downflow (PTD) and pitched turbine upflow (PTU) were employed. The impeller diameter to vessel diameter ratio was varied in the range of 0.25 to 0.58. The effect of impeller clearance from tank bottom was also studied. Mixing time was measured using the transient conductivity measurement. The PTD impeller was found to be the most energy efficient for mixing in liquid phase alone. Further, PTD (T/3) was found to be most energy efficient as compared with other impeller diameters. The effect of clearance was found to be design dependent and it was found to be diameter dependent in the case of pitched turbines. Flow patterns of different impellers have been studied by visual observations (using guide particles). These observatio...

Variable dilution ratio hose-end aspirator sprayer

Abstract: A multiple dilution ratio aspirator sprayer adapted to be connected to a hose for mixing a liquid with pressurized water from the hose and providing a spray of the mixture comprises a container for housing the liquid to be mixed with the water; a mixing head having a nozzle at one end thereof and a garden hose attachment device at the other end thereof; a mixing chamber within the mixing head; a hose for communicating the liquid from the container to the mixing head; a disk having a plurality of apertures therein rotatably mounted in the mixing head to control flow from the container to the mixing chamber; a flow tube communicates liquid in the container to the inlet to mixing chamber through a selected aperture in the disk so that the liquid is diluted with pressurized water at a dilution ratio determined by the size of the aperture aligned with the tube and the mixing chamber; and a cleaning orifice is positioned circumferentially from the mixing chamber so that each of the plurality of apertures may be selectively aligned therewith for cleaning.

Method and apparatus for fire control

Abstract: Method and apparatus for fire control comprising the use of a gas-liquid twin fluid spray nozzle. In one embodiment the spray nozzle comprises a mixing chamber having a gas inlet and one or more outlets at opposite ends, two or more liquid inlets between the gas inlet and the outlets and a mixing zone between the liquid inlets and the outlets. In another embodiment the spray nozzle comprises a mixing chamber having a plurality of gas inlets, liquid inlets and outlets, the inner surface of the mixing chamber being capable of aiding mixing of gas and liquid introduced through the inlets. The nozzles may be used in fixed, portable or semi-portable fire control systems.

Phosphorus recovery from

Abstract: A process for recovering phosphorus from phosphorus-containing pond sludge having a phosphorus concentration of from about 5% to about 70% by weight, the sludge being an emulsion of phosphorus in water, the process is described comprising the steps of: (a) mixing the pond sludge with additional water and heating the mixture in a vessel under mild agitation at a temperature of from about 165/sup 0/F to about 212/sup 0/F for at least about one-half hour to increase the phosphorus concentration in the sludge, the mild agitation being effective to prevent the formation of layers of different composition within the vessel, (b) allowing the concentrated sludge to settle to the bottom of the vessel; (c) introducing water at a temperature of from about 130/sup 0/F to about 150/sup 0/F into the vessel to wash the concentrated sludge, (d) repeating step (a) to further increase the phosphorus concentration in the sludge from step (c), and (e) recovering the sludge from step (d).

Superconductive body having improved properties

Abstract: Some mechanical, electrical, and thermal properties of high T c superconductors such as (Ba, Y) cuprates can be substantially improved by the dispersal of an appropriate metal in the superconductive body. For instance, mixing Ag particles with superconductive powder of nominal composition Ba₂YCu₃O₇ and processing the mixture in the conventional manner can produce superconductive bodies having T c of about 93K and substantially greater fracture strength and normal state electrical and thermal conductivity than otherwise identical bodies that do not contain Ag particles.

Effects of preparation techniques on the porosity of acrylic cements

Abstract: We investigated four acrylic cement preparation techniques for their effects on cement porosity: hand mixing, pressurization in a pneumatic pistol, centrifugation, and vacuum mixing. All the techniques were tested on three types of cement with different viscosity characteristics. The best results were obtained with vacuum mixing using a newly designed experimental system, yielding porosity reductions of 60-80 percent relative to hand mixing. Vacuum mixing with a commercial system was also effective, but to a somewhat lesser extent. Pressurization and centrifugation had no substantial effect on the overall porosity. Centrifugation led to considerable nonuniformity in the distribution of pores and additives.

Quench assembly design

Abstract: According to this invention, a quench assembly having improved mixing efficiency comprises a series of mixing zones: quench fluid inlet zone; quench mixing zone; a jet stirred mixing zone; and a distributor zone. In the quench fluid inlet zone, quench fluid is introduced to fluid from the catalytic bed above. The quench fluid is introduced through holes in a quench pipe, creating jets of quench fluid which entrain and mix the reactant fluid, typically partially reacted, from the bed above. This mixing zone is separated from the quench mixing zone by means of a horizontally disposed plate having a central opening therein. The reaction fluid and quench fluid enter the quench mixing zone through the central opening in the plate separating the two zones and impinge on a bottom quench mixing zone plate, where the gases are turned radially outward and passed over and around a series of mixing baffles. A plurality of pipes is located in an annular ring near the periphery of the bottom plate of the quench mixing zone for introduction of the quench gas and process fluid into a jet stirred mixing zone. Thus, the flow of fluids coming out of the quench mixing zone is introduced in a swirling direction into the jet stirred annular mixing zone, where the fluids are further mixed by mutual entrainment. Next, the fluid is turned downwardly through a central opening in a plate separating the jet stirred zone from the distributor zone. The distributor zone is provided with a distributor tray for distributing the fluid to the catalyst bed below.

Review of Liquid Mixing in Packed Bed Biological Reactors

Abstract: The use of residence time distribution analysis to characterize the liquid phase hydrodynamics in bioreactors is reviewed, with special emphasis on packed bed bioreactors. The importance of tracer selection, the method of data analysis and other uses for the data collected in RTD measurements are discussed.

Preparation and combustion of fuel oil emulsions

Abstract: Apparatus for the preparation of emulsions of oil in water comprises: (a) an oil feed line, (b) a source of concentrated surfactant solution, (c) a source of water, (d) a first low shear mixer for mixing concentrated surfactant and water to form a dilute surfactant solution, (e) means for uniting the flows of dilute surfactant solution and oil in a controlled manner, (f) a second low shear mixer for mixing the united flow streams of oil and dilute surfactant solution to form an emulsion of oil in water, (g) a third low shear mixer for mixing the emulsion of oil in water to form a dilute emulsion, and, (h) an arrangement of water feed lines and control valves such that, firstly, water can be supplied either to the first low shear mixer only or, secondly, to both first and third low shear mixers. The apparatus is particularly suitable for the preparation of emulsions of fuel oil in water from oils within a wide range of viscosities which burn with low emissions of NOx and particulates.

Method and apparatus for continuous mixing of small, precise quantities of bulk materials with a liquid stream

Abstract: A continuous mixer (10) is provided for combining bulk materials metered at a relatively slow rate into a liquid stream and is particularly useful for preparing an innoculant solution for treating feed pellets, seed or the like. The mixer (10) has a vertical separation tube (48) extending between a screw feeder (38) and a mixing zone (64) in a liquid conduit (54) therebelow, and the tube (48) is independently pressurized with air to substantially preclude ascent of liquids within the tube to ensure that all of the mixing occurs within the liquid line and to prevent the liquid from rising to a level sufficient for wetting the innoculants stored within a hopper adjacent the screw feeder. Air pressure within the tube is selectively adjustable in order to vary the spray produced by a nozzle (70) at the end of the fluid conduit from a liquid stream essentially free of air to a finely dispersed fog which includes substantial quantities of air.

Method of streakless application of thin controlled fluid coatings and slot nozzle - roller coater applicator apparatus therefor

Abstract: A novel combined hot melt and other fluid preferably slot nozzle-roller coater assembly and technique enabling elimination of streaks and other aberrations caused by undissolved particles or dust and the like in the fluid, and adapted for multi-fluid mixing, if desired.

Concrete mixer having means for determining the consistency of concrete mixing therein

Abstract: A concrete mixer is disclosed having a mixing drum and a drag body is mounted in the drum which has a drag surface positioned to at least partially come into contact with concrete in the drum during a measuring phase in the concrete mixing operation. A hydraulic driving circuit is provided to oscillate the drag body at least during the measuring phase. A pressure sensor is connected in the hydraulic driving circuit for measuring the actual pressure value in the hydraulic driving circuit which is indicative of the flow resistance on the drag surface during the measuring phase of the mixing operation.

Coupling for mixing lotions or other liquids with shower water

Abstract: A coupling (10) for being mounted between the threaded end of the arm (16) of a shower through which water flows and the showerhead (18) for mixing liquid into shower water. The coupling (10) includes a coupling body (20) having an inlet portion and an outlet portion with a flow path defined therebetween. A mixing chamber (32) is mounted in fluid communication with the flow path through the coupling body (20) which serves to selectively mix liquid such as body lotion with the water. In this regard, a vacuum generated by a venturi serves to draw the liquid into the mixing chamber. The vacuum is selectively controlled by a vacuum actuator (52) which holds the vacuum until the shower is turned off.

Liquid and powder measuring apparatus

Abstract: A liquid or powder measurement apparatus, usable also for mixing a plurality of measured materials and for distributing the mixture to a plurality of dispensing containers. A flow control valve having a wide flow rate range and excellent linearity between the degree of valve opening and flow rate is disposed in each of the liquid flow paths and is adjustable to have a flow rate linearly varying with the stroke of the valve. A mixing container receives the raw material from one or more supply containers and is weighed by a load cell to thereby detect the amount of material flowing into or out of the mixing container. A control unit operating according to fuzzy logic compares the measured weight with a target weight and accordingly adjusts the flow rate of a selected one of the flow regulators. The same load cell and control unit can also control the flows from the mixing containers to the dispensing containers.

Axial gas mixing in a circulating fluidized bed

Abstract: Axial dispersion has been measured and characterized for a 0.152 m diameter by 9.3 m tall cold model circulating bed unit. Mixing was measured by making step changes in the inlet concentration of a tracer gas, helium, and monitoring the response at the riser exit. The results are interpreted both with the aid of a pseudo-dispersion coefficient and by rigorous Fourier transform techniques. Axial dispersion increases rapidly with an increase in solids hold-up in the riser. The geometry of the exit has a substantial influence on the dispersion at identical total solids hold-ups. Mixing can differ greatly from simple plug flow and from predictions of single phase axially dispersed plug flow models. A simple two-zone model is shown to provide a starting point for describing axial dispersion.

Preparaton of HIPR emulsions and transportation thereof

Abstract: An HIPR (high internal phase ratio) emulsion of oil in water is prepared by directly mixing 70 to 98% by volume of a viscous oil having a viscosity in the range 200 to 250,000 mPa.s at the mixing temperature with 30 to 2% by volume of an aqueous solution of an emulsifying surfactant or an alkali, percentages being expressed as percentages by volume of the total mixture. Mixing is effected under low shear conditions in the range 10 to 1,000 reciprocal seconds in such manner that an emulsion is formed comprising highly distorted oil droplets having mean droplet diameters in the range 2 to 50 micron separated by thin interfacial films. The emulsions are much less viscous than the oils from which they are prepared and may, optionally after dilution, be pumped through a pipeline. Viscous crude oils may be transported by this method.

Vortex ring mixers

Abstract: A method of mixing fluids and mixing equipment is disclosed wherein an orifice plate is caused to be reciprocated at right angles to the plane of the orifice plate in a fluid to generate a ring vortex through the orifice, the orifice in the plate and the stroke of the plate are defined by the relationship 0.8≦L/d≦3.8, where L is the stroke of the plate and d is the diameter of the orifice.

Foam generation in a rotor—stator mixer: schaumerzeugung in einem rotor—stator mischer

Abstract: The foaming process of an aqueous liquid system with surface active agents and thickeners in a rotor-stator mixer has been studied. The foaming capacity of a rotor—stator mixer may be represented by a so-called mixing characteristic. The foamabilities of several liquid systems have been measured as a function of the mixer geometry and the rotational speed. The hydrodynamics in a rotor-stator mixer is characterized by a Newton—Reynolds relationship. The mechanism of foaming and the dependence of several mixing parameters are different for the turbulent and laminar flow regions. The mixing process is evaluated in both regimes. In the transition region from turbulent to laminar the foaming is very poor in comparison with that in the turbulent and laminar flow regimes.

Device for dispensing and mixing at least two reactive components

Abstract: The reactive components to be mixed are contained in cartridges (42, 43), in each case two cartridges (42, 43) being connected to a mixing device (48) with the aid of one connecting line (46, 47) in each case. The aforesaid parts form a compact unit which cannot be disconnected by the user. Each cartridge (42, 43) is under the influence of a piston-like insert (44, 45), the cartridge being provided at the outlet end of the cartridge and/or at the side of the piston-like insert (44, 45) with a closure (68, 69) which opens under the effect of pressure. The outlet connecting piece (60, 61) of the cartridge (42, 43) is received in an insertion chamber (51) of a coupling part (50). The latter is arranged in stationary fashion and provided with a cutting element (52), against which the outlet connecting piece (60), equipped with a closure diaphragm (68), of the cartridge (42) can be axially displaced. By displacing the cartridge (42), the diaphragm (62) is broken and the contents of the cartridge released so that the contents pass under the effect of pressure into the mixing device (48).

Mixer for pulverous and liquid materials (essentially cement and water), of liquid-liquid materials

Abstract: The invention consists of a centrifugal mixer with an upper rotor (3) for projection of particles, which is hard-mounted to rotor (4) allowing centrifuging of fluid (15). The invention lies in the creation of a low-pressure zone within the high-pressure zone of enclosure (23), for introduction of particles (20); this in turn requires the use of disturber (27). The result is a remarkable degree of mixing of the water and cement and has applications for oil field services.

Production of low ash lignin

Abstract: A process for the production of lignin in which lignin is precipitated from aqueous solution by acidification and agitation and the precipitated lignin is separated from accompanying liquid in which the lignin-containing solution and the acid are introduced by simultaneous cocurrent flow into an agitated mixing region, the precipitated lignin is separated not more than 60 minutes after precipitation and the separated lignin is subsequently washed. The process can form a step in a general process for the treatment of lignocellulosic materials to produce one or more products including lignin. The process enables the ash content of lignin to be reduced.

System for manufacturing solid medium

Abstract: A system for manufacturing a solid medium for cultivating mushrooms includes a mixer for mixing and agitating medium materials, and a heater coupled to the mixer for sterilizing the medium materials from the mixer with the heat of steam. The sterilized medium materials are then delivered into a cooler connected to the heater, and cooled and moistened by water scattered by a sprinkler. The cooler is coupled to a mycelia supply source for supplying mycelia of the mushroom with which the cooled medium materials are spawned. The solid medium thus produced is then packaged by a packaging mechanism in a germ-free environment.

Polymer-asphalt mixing process

Abstract: The present invention relates to a two stage process for the incorporation of plastic and ethylene-propylene rubber into asphalt. In the first mixing stage, a rubber-rich masterbatch is prepared by mixing asphalt, plastic and the rubber. In the second stage of mixing, additional asphalt is mixed with the masterbatch. The first stage is completed in polymer mixing equipment while the second stage is completed in asphalt mixing equipment. The present process provides a convenient process to incorporate polymer into asphalt, in comparison to prior art processes wherein the polymer is added directly to the asphalt.

Low pressure mixing apparatus for atomizing fluids

Abstract: The liquid feed injector as hereindescribed uses sequential stages of increased severity mixing to fully atomize a liquid portion of a combined liquid and gaseous stream. Sequential mixing consists of a first mild mixing that takes place in a mild mixing zone and blends the liquid and gaseous material into a substantial uniform mixture. The uniform mixture of liquid and gaseous material passes through another stage of vigorous mixing where the liquid is sheared and gas is dispersed throughout the liquid by dividing the mixture into a plurality of small streams and directing the projection of the streams into impingement with an impact medium to produce a homogeneous mixture of fine gas bubbles dispersed in the liquid. The homogeneous liquid and gas mixtures are then discharged through one or more discharge nozzles to effect atomization and distribution of the liquid in a suspension of fluidized solids. The sequential stages of increased severity mixing allow atomization of the liquid into fine droplets with a reduced pressure drop across the discharge nozzles. In a highly preferred form, the liquid injector includes provisions for injecting two fluid streams into a suspension of fluidized solids at two discrete locations.

Method for homogenizing a mixture of aqueous residual liquid or solid fuels

Abstract: The invention relates to a method which makes it possible to produce homogeneous mixtures of industrial wastes such as polluted waters, hydrocarbon wastes and various coal grades, as well as combustible industrial wastes. An essential feature is that the homogeneous mixtures produced in accordance with this invention are stable, and lend themselves to being pumped and injected. According to the invention, this method consists in forming during a first stage a stable emulsion of oily combustible material in water and during a second stage, in mixing this emulsion with a solid or liquid combustible material.