Abstract: An electrostatic separator of the free-fall type for classifying triboelectrically charged substance mixtures. This separator has a separate voltage source connected to each of the electrodes forming a pair of electrodes in such a way that the one voltage source supplies a positive voltage against ground potential and the other voltage source supplies a negative voltage against ground potential. This causes the potential difference against ground to be equal to zero in the center of the separator.

Abstract: A free-fall separator apparatus for mixed particles. The apparatus includes a screw feeder for triboelectrically charging the particles, a feed hopper for releasing the tribocharged particles in a laminar flow path between a first electrode structure and a second electrode structure. The first electrode structure provides corona charging for the falling particles, and a substantially uniform electrostatic separation field is provided between the electrode structures for separating the falling particles. The electrode structures may each include a plurality of vertically extending string electrodes. Also provided is a method for sorting mixed particles which includes steps of charging the particles through contact electrification, releasing the mixed particles to fall freely in a substantially laminar stream, charging the particles electrically through corona discharge, and separating the particles through an electrostatic separation field.

Abstract: A force field separator which can utilize either electric or magnetic fields to separate materials which are sensitive to those forces. As an electrostatic precipitator it produces higher separation efficiencies with smaller equipment and lower cost. As a magnetic separator it separates paramagnetic and diamagnetic materials with lower strength fields. It employs small sectional area rods which generate high field gradients between adjacent rods which are oriented at an angle to the flow direction inside an elongate housing which contains the fluid stream. The separation forces are a resultant of the force propelling the fluid through the housing and the field forces produced by the field gradients. The resultant force direction is towards multiple openings along the outside length of the housing where a separate plenum flow of separated materials is created.

Abstract: In a belt separator system for separating constituents of a mixture of particles, the belt having a leading deflective surface at an acute angle to the direction of belt travel so as to impart a transverse momentum component to the constituent in a direction toward a longitudinal centerline of the belt separator system.

Abstract: A belt-type counter-current separator for separating a mixture of particles, including conductive particles, includes a voltage radiant assembly having a plurality of conductive elements inter-disposed with a plurality of dielectric elements. The plurality of conductive elements are coupled to respective nodes of a voltage dividing circuit for dividing a voltage between a high potential electrode, of the electrostatic separator, and a reference potential. The plurality of conductive elements and dielectric elements in combination with the voltage dividing circuit limit a voltage potential between any adjacent conductive elements to a maximum potential so as to prevent sparking due the presence of conductive particles in the separator. In one embodiment of the separator, the voltage gradient assembly is an extruded plastic material having both conductive and non-conductive elements and pieces of alumina are disposed between the conductive elements to provide a durable voltage gradient surface.

Abstract: Various forms of micromachined electrostatic microconveyors and useful devices based thereon are described. In one embodiment, a tube shaped conveyor is formed by disposing conductors circumferentially about the exterior surface of the tube. The tube is formed of an insulating material (e.g., silicon dioxide). Driving voltages are applied in staggered phase to selected ones of the conductors to provide a travelling electrostatic wave within the tube. Charged particles (or fluid or gas) can be propelled through the tube electrostatically by "riding" the travelling wave. Various aspects of the invention are directed to apparatus making use of the microconveyor to convey particles, gas ions, etc. Apparatus is described for using gas pressure resulting from the transport of gas ions to do mechanical work (i.e., to operate mechanical actuators.

Abstract: Improved belt for a charged particle separation system, the belt being an extruded article made from a host polymer and additive composition. The host polymer and additive are selected to yield a belt with tailored properties such as wear resistance, creep, coefficient of friction, and charging properties.

Abstract: A friction electrifying-type electrostatic sorting apparatus having a preliminary friction electrifying unit for preliminarily electrifying a sorted material by providing a friction; a friction electrifying unit for further electrifying the sorted material having been preliminarily electrified by the preliminary friction electrifying unit; a feeding unit for supplying the sorted material having been electrified by the friction electrifying unit; and an electrostatic sorting unit for electrostatically sorting the electrified material supplied from the feeding unit according to the electrified state of the sorted material by providing the sorted material in an electrostatic field.

Abstract: Electrostatic separation is used to separate electrically conducting particles from electrical insulator particles by attracting the conducting particles to a separating electrode, whilst the insulator particles remain substantially attached to a carrier electrode. The electrical properties of the particles to be separated can be enhanced or even changed by controlling the moisture content of the particles to be separated.

Abstract: An electrostatic sieve having a circular solid electrode, preferably with sawtooth contours arranged on its lower side concentrically around a center hole. The solid electrode is supported by insulating brackets around its perimeter. The brackets are attached to a conical outer structure, which also serves to collect the coarse particles. Underneath the solid electrode, with a gap between, is the sieve electrode, which is supported by a stretcher, preferably a circular ring of tubing with a square cross-section, itself supported on insulating brackets, which rest on an inner cone. The inner cone tapers toward the bottom to collect the fine powder passing through the sieve electrode, which passes through the hole in the bottom of the cone and falls into a collecting tray. The outer surface of the inner cone forms the inner surface of a conical passage, the outer surface of which is the outer conical support. Powder to be sieved is fed into the opening in the center of the solid electrode.

Abstract: There is disclosed an electrostatic separation and classification apparatus (20) which includes a pair of electrode unit mechanisms (21, 22) having spaced electrodes (28, 29), insulative endless belts (30, 31) covering opposite surfaces of the electrodes (28, 29) and opposed to each other for feeding in circulation, and deposit scratching members (38, 39) remote from a position in which an electrostatic field produced between the electrodes (28, 29) works and in contact with outer surfaces of the endless belts (30, 31) throughout their width, respectively, thereby increasing the rate of operation and safety.

Abstract: The present invention is a method and apparatus for further reducing the size of nanoparticles. Nanoparticles are defined as having an effective average particle size of less than about 400 nm. The present invention separates the nanoparticles further using electric fields.

Abstract: A method of separating mixtures of microscopic dielectric particles in sunsions in an apparatus for carrying the method. A mixture of particles is forced onto guide paths by dielectrophoretic forces or by a flow of the suspension medium with an additional force, which is provided to compensate the force causing the particles to move along the guide paths for specific particle species causing the specific particle species to be fed out from the mixture of particles. The apparatus may be integrated on surfaces of silicon wafers at low cost and in mass-production numbers, and is suitable for isolating minute particles such as biological cells, cell organelles, bio molecules as well as organic dielectric particles.

Abstract: Separation of a mixture of plastic materials by separating the plastic mixture according to particle size, and introducing plastic of similar size particles into a vertical fluidized bed column having an upwardly flowing gaseous stream therein. The flow rate of the gaseous stream is controlled to provide a relatively low density fraction of the plastic mixture exiting at the upper end of the column, and a relatively high density fraction of the plastic mixture exiting at the lower end of the column. In one embodiment, electrostatic charges are induced on the particles of the plastic mixture prior to introducing the plastic of similar size particles into the column, and the column is charged to attract thereto the plastic particles having the highest electrostatic charge.

Abstract: Apparatus for separating one type of particle from a mixture of particle types by dropping the mixture through a free fall zone between two spaced vertical walls of electrostatically charged, vertical cylindrical, spaced, continuously rotating electrodes that are continuously brushed by a plurality of spaced vertical cylindrical continuously rotating brushes.

Abstract: Apparatus and method for the separation of particles in either a liquid or gas stream is provided. The fluid stream is directed in a swirl-flow pattern to develop thereby centrifugal forces on the stream. Optionally, magnetic and/or electrical fields may be applied to the system to enhance separation of the particles. Air sparging may also be employed to further enhance the separation of hydrophilic particles from hydrophobic particles in a liquid system. Optionally, the swirl-flow pattern may exit the downstream end of the separator where a stream splitter is employed to split the swirl-flow pattern stream which splays outwardly at the outlet in two or more streams which carry desired particles to be recovered.

Abstract: A process for the separation of corn fiber from dry-milled corn. The corn fiber is separated frm the dry-milled corn by employing a Multified Electrostatic Separator using dielectrophoresis.

Abstract: Particles having different properties (e.g. particulate fly ash and carbon) are separated by driving the particles by means of a vibratory feeder (12) forwards along a horizontal electrode plate (1) above which is mounted a second electrode (2) having at least one plate (4) mounted at an acute angle (.alpha.) to the horizontal. Preferably, two plates (4) each extend sideways from a central block (3) of dielectric material. An alternating electric field is generated between the electrodes (1, 2) by a high voltage AC power source (14). The potential across each plate (4) varies (in particular, decreases) in the lateral direction, the variation being continuous or stepwise. The field lines (16) from each plate (4) curve to the side and impart centrifugal forces to particles charged by friction or conductive induction, which forces separate lighter, more heavily charged particles from the others. The separated particles are collected in bins (13) arranged around the lower electrode (1).

Abstract: Particles having different properties (e.g. particulate fly ash and carbon) are separated by moving the particles forwards along a horizontal electrode plate (1) above which is mounted a second electrode (2) having two plates (4) each extending sideways from a central block (3) of dielectric material at an acute angle (.alpha.) to the horizontal. An alternating electric field is generated between the electrodes (1, 2) by a high voltage AC power source (14). The field lines (16) from each plate curve to the side and impart centrifugal forces to particles charged by friction or conductive induction, which forces separate lighter, more highly charged particles from the others. The separated particles are collected in bins (13) arranged around the lower electrode (1), which electrode is mounted on a vibratory transducer (12).

Abstract: Developer mix is regenerated in a manner which removes toner crusts from carrier particles in order to extend the useful time of a developer mix within a developer station of an electrophotographic printing or copying machine. A portion of the developer mix is continuously removed from the main body of developer mix in the developer station and supplied to a regenerator device where the developer particles are swirled and impacted to flake off the toner crust formations. The regenerator device is formed with a discharge opening for removal of the cleaned or regenerated developer mix. The discharge nozzle is connected to a recirculation line through which the regenerated mix is conducted back into the developer station. The regenerator device is further provided with an extraction opening for removing the flaked off crust particles to a separate area, such that crust particle deposits are prevented from building up in the regenerator device.

Abstract: Calcined trona and/or nahcolite bearing ore particles are separated into a plurality of fractions of relatively uniform particle size. Those calcined particles smaller than about 6.7 mm in size and larger than about 0.2 mm in size are passed through an electrostatic separator to obtain an ore concentrate containing a greater percentage of soda ash and a lesser percentage of insoluble impurities than were present in the ore; a middling fraction and an ore tailing fraction containing a lesser percentage of soda ash and a greater percentage of insoluble impurities than were present in the ore. The middling fraction may be recycled to increase the yield of ore concentrate. Calcined particles smaller than about 0.2 mm may be combined with the ore concentrate. The combined ore concentrate fraction may be marked as technical grade soda ash or used as a high grade feed to a monohydrate refining process.

Abstract: An electrostatic sorting apparatus having a multistage sorting unit including a plurality of sorting conveyor belts on sorting plates aligned vertically within a cover housing. Each sorting conveyor belt or plate has a trough-like channel formed thereon for sorting a mixture of insulating particles and conductive particles. The particles of the mixture are subjected to repeated cycles of charging with a negative polarity, being attracted to a high voltage electrode, discharging, and dropping downwardly into sorting and recovering hoppers. Thus, the particles are vigorously elevationally moved between the sorting conveyor belt or plate and the electrode up and down and are finally collected in hoppers. The particles are accordingly uniformly agitated in the channel of the sorting conveyor belt or plate. Thus, the mixture is separated into the hopper with an enhanced quality of compost while fine foreign materials mixed therewith are removed from the compost.

Abstract: An electrostatic separator for separating or removing materials according to their polarizability which comprises a cylindrical surface having a plurality of closely spaced conductors embedded in an electrical nonconductor with the surface adapted to be rotated about its longitudinal axis in close proximity to the material from which loose particles are to be removed. The cylinder is rotated through successive zones wherein the surface of the cylinder is charged while in close proximity to said material causing the particles to migrate to the surface, then through a zone wherein the surface is oppositely charged so as to repel particles therefrom, and collecting and disposing of the particles removed from the material. This apparatus and method has many applications wherein fibers, dust, contaminants, and the like may be removed from the desired product.

Abstract: The separator charges the particles to be separated and passes them through an alternating electric field which has a non-uniform intensity in a direction perpendicular to the forward direction, and which also has field lines curved in the same direction. The particles which move along the curved field lines due to their charge are thus subjected to a centrifugal force which effects their separation. The separator includes a pair of conductive electrodes, the first being substantially horizontal or possibly at an angle from the horizontal and the second mounted facing the first at a predetermined angle to it. The electrodes may be planar or curved. The field is supplied by an ac source operating in the range of 3 to 1000 hz. A mechanical vibrator attached to the first electrode imparts the forward motion to the particles.

Abstract: First and second developing units (66), (67) apply toners of first and second colors respectively to a photoconductive drum (61) carrying a bipolar electrostatic image to form a bicolor toner image. A small amount of the first toner is scraped off the drum (61) in the second developing step and becomes mixed with the second toner in the second developing unit (67). The admixed first toner is separated and removed from the second toner by a separation member in the form of a roller, belt or mesh covered electrode (81) which is charged to a polarity opposite to the first toner and electrostatically attracts the same while repelling the second toner.

Abstract: Soda ash is produced from crude trona ore in a novel process which comprises(a) reducing the ore particle size to a maximum of about 4.0 millimeters in diameter,(b) removing fines from the ore to produce a minimum particle size of about 0.1 millimeter in diameter,(c) differentially electrifying the ore particles according to differences in conductance,(d) segregating the ore particles by electrostatic separation into at least two fractions according to the differences in electrical charge resulting from the electrification of step (c), and(e) calcining the fraction of least conductance to convert the trona contained therein to soda ash,steps (a) through (d) occurring at a temperature not to exceed about 100.degree. C.

Abstract: Apparatus for separating non-ferrous metal from waste material comprising a grounded rotary conductive drum, means for feeding waste material to the drum, a D.C. corona electrode, an A.C. corona electrode, a D.C. static electrode and a splitter. The method of separation comprises magnetic separation of ferrous metals, sizing of the waste material, preliminary classification to remove dust and low density particles, drying to reduce the moisture content, feeding the waste material to the rotating grounded roll and subjecting the material successively to D.C. corona discharge, A.C. corona discharge and a D.C. electrostatic field.