Abstract: Patterned platelets are platelets made with specified shapes and sizes. The various sizes and shapes of the platelets are used to code articles and substances to which they are applied. The patterned platelets can be in inks or paints applied to articles. The platelets can be further coded by markings thereon or by spectral or polarization codes rather than just the distribution of sizes and shapes. The patterned platelets can be made from any materials buy subtractive or additive processes. A patterned platelet can also be made by an actinic polymer being applied to a substrate and a mask applied to allow only the desired size and shape to be exposed to radiation curing the unmasked portion of the polymer on the substrate. The polymer can be cholesteric liquid crystals with the properties of reflecting polarized light of selected wavelengths to code the crystals in addition to the size and shape codes.

Abstract: A condensation nucleus counter has a series of flow passageways forming a flow path, including a first passageway for carrying the gas stream having the particles to be detected which is heated, so that the gas stream is heated prior to entering a saturator. The saturator is positioned as part of the flow path for the gas stream and is made of a porous material having a portion immersed in a liquid working fluid. The porous material is selected so that capillary action will move the liquid working fluid along the length of the saturator. Vapor from the working liquid will be transferred to the gas stream as it moves through the saturator. The gas stream then passes to a condenser or cooler that reduces the temperature of the gas stream and causes the working fluid vapor to condense on the particles in the gas stream to form droplets. A particle detector, such as a light scattering particle detector, then receives the gas stream and detects the droplets that have been formed.

Abstract: A wide range particle counter has sections which separately detect coarse and fine particles in an aerosol. The coarse particles are counted and sized in an optical particle counter. The fine particles are classified with a differential mobility analyzer to determine size and then passed through a vaporizer and condenser and also counted. Using the different sections permits counting and measuring a wide range of particle size in a single instrument with high accuracy and reliability.

Abstract: This invention relates to methods and systems for detecting contaminants that can precipitate and deposit on a workpiece during a carbon dioxide application, especially contaminants that are already present and dissolved in the fresh carbon dioxide fed to the application. One aspect of this invention includes a method of detecting contaminants dissolved in a carbon dioxide stream, including the steps of sampling at least a portion of the carbon dioxide stream to form a carbon dioxide sample; modifying at least one physical condition of the carbon dioxide sample to form an aerosol that includes gaseous carbon dioxide and at least one suspended contaminant; and detecting the number of particles of suspended contaminant in at least a portion of the carbon dioxide sample with at least one particle counter. A system for continuously detecting contaminants dissolved in a carbon dioxide stream is also described.

Abstract: A fast mixing condensation nucleus counter useful for detecting particles entrained in a sample gas stream is provided. The fast mixing condensation nucleus counter comprises a detector and a mixing condensation device having a mixing chamber adapted to allow gas to flow from an inlet to an outlet, wherein the outlet directs the gas flow to the detector. The mixing chamber has an inlet for introducing vapor-laden gas into the chamber and at least one nozzle for introducing a sample gas having particles entrained therein into the chamber. The inlet and nozzle are arranged such that the vapor-laden gas and sample gas mix turbulently. The mixing chamber is configured such that the particles flow through the mixing chamber at a substantially uniform relative velocity.

Abstract: A cloud condensation nucleus spectrometer having a streamwise segmented condensation nucleus growth column. The condensation nucleus growth column includes alternating hot and cold temperature-maintaining segments arranged next to one another. The temperature difference between adjacent hot and cold temperature-maintaining segments increases from the input opening to an output opening of the condensation nucleus growth column to produce a supersaturation distribution that increases from the input opening to the output opening.

Abstract: A condensation nucleus counter (CNC) device implemented with a multi-directional fluid flow system is configured in a compact, conical geometry. A saturation region includes an inlet that delivers into an annular pool a sample stream of air containing small-diameter particles. The stream of air flows out and expands radially from the inlet and mixes with a working vapor to become saturated in the saturation region. The saturated fluid mixture then flows to a condensation region defined by spaced-apart inner and outer radially converging walls having a conical geometry, thereby forming an annular flow volume of decreasing cross sectional area in the direction of fluid flow to the outlet of the CNC device. The working vapor condenses on the small-diameter particles to enlarge their sizes with less tendency to condense on the inner walls of the condensation region.

Abstract: A method and apparatus for determining the presence of molecules in a gas at concentrations of less than about 100 ppb. Light having wavelengths in the range from about 200 nm to about 350 nm is used to illuminate a flowing sample of the gas causing the molecules if present to form clusters. A mixture of the illuminated gas and a vapor is cooled until the vapor is supersaturated so that there is a small rate of homogeneous nucleation. The supersaturated vapor condenses on the clusters thus causing the clusters to grow to a size sufficient to be counted by light scattering and then the clusters are counted.

Abstract: An apparatus and a method are disclosed for detecting particles in a particle-containing gas at a pressure greater than about 0 psig. The apparatus includes a gas distribution line containing a pressurized gas having a pressure greater than about 0 psig and a condensation nucleus counter in fluid communication with the pressurized gas in the gas distribution line. The condensation nucleus counter is adapted to receive a stream of the pressurized gas at a pressure substantially equal to the pressure of the pressurized gas in the gas distribution line. The condensation nucleus counter is constructed of materials resistant to corrosion and to reaction with the pressurized gas, which may be one or more reactive or toxic gases, such as those used in microchip processing, or an inert gas.

Abstract: A method and apparatus for quickly detecting the surface characteristics of a surface, such as features, anomalies or contaminants are disclosed. The method and apparatus use heterogeneous condensation of a vapor on a surface and evaporation to reveal the surface characteristics of the surface and thereby enable the detection of such features.

Abstract: The present invention is directed to a system for converting between single flow and split flow evaporative light scattering detection devices for detecting samples in a mobile phase. Included in the system is a evaporative light scattering detection device, a low temperature adaptor, and a connection tube for providing a fluid connection between the evaporative light scattering detection device and the low temperature adaptor.

Abstract: An aerosol detection system for measuring particle number distribution with respect to particle dimension in an aerosol sample. The system includes an alternating dual-bag sampler, a radially classified differential mobility analyzer, and a condensation nucleus counter. Pressure variations in sampling are compensated by feedback control of volumetric flow rates using a plurality of flow control elements.

Abstract: The present invention is directed to a device for evaporative light scattering detection that can be used for a wide range of sample types and mobile phases. The device may be quickly converted between a single flow and a split flow configuration through the use of a retractable impactor.

Abstract: An evaporative light scattering detector (1) has a solvent nebulizer (4) through which an atomised spray of solute solvent solution passes, a heated evaporation chamber (5) and a detector system (6). A diffuser trapping device (7), supported by fine wires, is positioned in the evaporation chamber(5) at about two fifths of the height of the chamber from the top. The diffuser trapping device (7) is made from randomly coiled stainless steel ribbon which gives it a large surface area. The detection system (6) is positioned at the bottom of the evaporation chamber through which a beam of collimated light passes and is scattered by the solvent and detected by a light sensitive device (14). The diffuser trapping device (7) aids evaporation of the solvent and prevents large particles from travelling further down the evaporation chamber (5).

Abstract: A modified mixing-type condensation nuclei counter for measuring the size and number of small particles is presented. A gas stream is saturated with respect to a working fluid. The saturated gas at a first temperature is mixed in a growth chamber with a sample gas at a second temperature that is lower than the first temperature. The mixture of the saturated gas and the sample gas at different temperatures results in supersaturation of the mixed gas with respect to the working fluid. Particles in the sample gas act as nucleation sites for condensation of the working fluid. The particles are thus grown to a larger size and therefore are more easily measured by known light-scattering particle detection methods. The efficiency of the supersaturation process is made even more efficient by cooling the growth chamber to a third temperature which is lower than the second temperature or by turbulently mixing the saturated gas and the sample gas.

Abstract: A particle counter of the condensation nucleus type wherein a primary stream of fluent material containing particles enlarged by vapor condensate of a working fluid flow through a viewing volume. A secondary stream of fluent material, termed purge gas, surrounds the primary stream of fluent material as the primary stream traverses the view volume, thereby providing a boundary layer of fluent material, reducing turbulence of the primary stream. The two streams are merged after passing through the view volume and the merged stream is drawn into one or more coalescent filters for conversion of vapor to working fluid which is then recycled for reuse, thereby extending the life of the working fluid and preventing escape of vapor which might contaminate the ambient environment.

Abstract: A condensation nucleus counter features an entropy control mechanism to regulate the entropy of a vaporized fluid present in a saturator, thereby facilitating supersaturation of the same about particulates entrained in a sample gas stream before the same passes through a condenser. The condensation nucleus counter includes a supply of sample gas, conduits adapted to allow the sample gas stream to flow therethrough, a saturator, a condenser and an optical detector, all of which are in fluid communication with each other. The manifold is disposed between the conduit and the saturator, and also a temperature control device. The manifold comprises a feed chamber and a plurality of channels positioned so that the sample gas stream entering the feed chambers evenly divides into a plurality of flows, with each flow entering the saturator. The temperature control device regulates the temperature difference between the flows entering the saturator and the vaporized fluid contained so as to be within a specified range.

Abstract: A condensation nucleus counter includes a saturator and a condenser with a thermoelectric device (TED) to simultaneously cool the condenser and heat the saturator. A controller is featured which operates the TED to maintain the temperature differential between the saturator and the condenser to within .+-.1.5.degree. C. at steady state. The controller may be set by a user to operate at any desired setpoint temperature.

Abstract: An improved method of monitoring condensate quality in a condensate return system and of controlling the level of particulate matter in the condensate flow so that when this level exceeds an acceptable limit, valves for discharging the condensate flow from the system open automatically or, alternately, an alarm is sounded. Utilization of the method facilitates the conservation of hot steam condensate for reuse in a boiler while preventing water contaminated with particulate matter from returning to the boiler, thereby protecting it from certain types of deposits and corrosion. The improved method includes measuring, on a continuous basis, relative numbers of particulate-type impurities under conditions in which rust or other particles large enough to block flow into a particle counter can be produced in sudden surges. Tests show that a suitable instrument for measuring the impurities under such conditions is a particle monitor.

Abstract: The concentration of non-volatile residue in a test solvent is determined by generating multiple liquid droplets from a liquid stream including the solvent and ultrapure water. The droplets are dried to form a stream of multiple particles of the non-volatile residue. A supply of ultrapure deionized water is caused to flow continuously toward a non-volatile residue monitor, at a constant fluid flow rate. Upstream of the residue monitor, a syringe is provided for intermittently injecting a test solvent into the fluid stream. In one case, the solvent is injected for several minutes at a constant flow rate substantially less than that of the ultrapure water. A mixing valve, downstream of the point of solvent introduction, causes turbulent flow to thoroughly mix the solvent and water. In an alternative approach, a syringe is used to instantaneously inject solvent in the form of bursts.

Abstract: In a system for measuring minute concentrations of dissolved solids in liquids, seed particles of a known diameter are mixed with the liquid and the mixture of the seed particles and the liquid is atomized into droplets of a known size. The droplets are dried to residue particles comprising the seed particle surrounded by a shell of the dissolved solid. The size of the residue particles are measured by passing the residue particles through a laser beam to scatter light to photodetectors so as to generate a pulse from each particle. The amplitude of the pulses will indicate the size of the residue particle from which the thickness of the shell and the concentration of the dissolved solid can be determined.

Abstract: A system for monitoring and analyzing impurities in a liquid by analyzing the non-volatile residue of droplets of the liquid includes a droplet generator for generating a stream of droplets of the liquid, a droplet inspection unit, a drop-on-demand unit for removing selected droplets from the stream of droplets, a heat exchanger for drying the droplets to provide non-volatile residue particles, and a particle size measurement unit. The droplet inspection unit determines the diameters of the droplets. A feedback arrangement from the droplet inspection unit controls droplet diameter by varying the droplet generation rate. The drop-on-demand unit removes a selected fraction of droplets from the droplet stream so as to reduce vapor loading in the heat exchanger and prevent agglomeration of droplets. The heat exchanger includes a first section for gradually increasing the temperature of the stream of droplets and a second section for maintaining the stream of droplets at the boiling temperature of the liquid.

Abstract: An electrospray nebulizer generates an aerosol comprised of submicrometer droplets substantially uniform in size. A liquid sample is supplied at a controlled rate to a capillary needle of the nebulizer, and droplets are formed due to an electrical field in the region about the needle discharge. The tendency of the droplets to disintegrate due to Coulomb forces is counteracted by sources of ionizing radiation within the nebulizer. The ions reduce the charge in each droplet while solvent evaporation reduces the diameter of the droplet. To further ensure against Coulomb disintegration, a controlled air sheath is introduced to the nebulizer for transporting droplets more rapidly downstream. Optionally, solvent vapor can be introduced into the air flow to reduce the rate of solvent evaporation within the nebulizer, and ions can be added to the air flow upstream of the needle discharge.

Abstract: A condensation nucleus counter has a humidifier zone, through which the sle air is guided, and an approximately perpendicularly arranged condensation zone, as well as an optical detection system with a light source and detector. The humidifying zone has a duct made of a permeable material and a hollow space surrounding this duct, the hollow space being used for receiving the process fluid. The condensation zone has a duct which, in turn, has a hollow space used for receiving the coolant. The condensation zone is connected with the humidifying zone by a connection piece.

Abstract: A continuous flow condensation particle counter employs a working fluid to saturate a gas stream, and then condense onto particles carried in the gas stream as the stream is directed through a condenser and cooled below the supersaturation point. A porous saturation block is positioned beneath the condenser, and receives droplets of working fluid condensate and water as the droplets descend from the condenser by gravity. The saturation block is constructed of a hydrophobic material, whereby it allows the working fluid to pass through but retains water within a collection reservoir centered below the condenser. A vacuum pump and a periodically actuated solenoid valve are employed to introduce a partial vacuum to the reservoir and thereby evacuate accumulated water. The preferred working fluid is a perfluorinated hydrocarbon fluid that is substantially odorless, chemically inert and non-flammable. Water is immiscible in the working fluid, and thus readily separable.

Abstract: An apparatus for measuring nonvolatile residue concentrations in liquid is disclosed. A plurality of fixed and adjustable flow restrictive elements are utilized and arranged in-line from a fluid supply source to provide a constant, pressure controlled flow of liquid to the measuring apparatus and allow for real-time measurements and optimal concentration detection. An atomizer atomizes the liquid into droplets which are dried to nonvolatile residue particles. The nonvolatile residue particle concentration is then determined utilizing an electrostatic aerosol detector. The invention further discloses apparatus for collecting a sample of nonvolatile residue for analysis and identification using a corona precipitator.

Abstract: A measurement system for microelectronic clean rooms to measure ultrafine particle size distribution in the range of 0.002 to 0.2 micrometers is provided which includes four screen diffusion stages each connected in series with a condensation nucleus detector. The input to each screen diffusion stage is connected to a localized area to be measured, and the output of each condensation nucleus detector is connected to a vacuum system which simultaneously draws particle bearing air through the four channels. The output signals of the condensation nucleus detectors present particle size distributiion. In one embodiment of the present invention, one or more optical particle detectors are connected in parallel with the diffusion stage-condensation nucleus detectors to expand the distribution measurements to larger sizes.

Abstract: A process for counting and sizing particles in gases in the size range of 0.0025 micrometers or greater using condensation nucleus counting wherein the condensing temperature of a saturated working fluid is incrementally adjusted to adjust sensitivity to differing sizes of particles and thus discriminate according to size.

Abstract: A device consisting of a monolithic block of material that is used as a housing of an apparatus for determining the density, or changes in density, of small particles, that contains an elongated chamber formed within the block that serves as a cloud chamber, and a trough formed in said block and defining a humidification chamber. The block includes passageways that connect the cloud chamber to the humidification chamber and inlet and exhaust passageways, as well as providing mountings for various valves, such as a humidity valve, by-pass valve, and vacuum valve used in the apparatus.

Abstract: Method and apparatus for sampling the gaseous medium of a zone or area to determine the concentration, or changes in concentration, of submicron particles suspended in the gaseous medium of that area or zone using an elongated cloud chamber. A light source and a phototransistor are disposed in the cloud chamber and spaced apart so as to be electronically responsive to varying levels of light. A microprocessor is connected to a programmable memory EPROM and has pre-programmed data instructions on particle concentration levels. The EPROM sequences the microprocessor to operate the valves that sequentially sample the gaseous medium in the cloud chamber, and opens the exhaust valve in the cloud chamber to create a condition of reduced gas pressure therein. The sample of gaseous medium containing submicron particles then precipitates or condenses a portion of the cloud in the chamber in proportion to the concentration of the particles.

Abstract: A method and apparatus for detecting and classifying particles on a surface in which condensation is used to enlarge particles. An apparatus of the present invention includes a heatable wick disposed over a test surface and in fluid communication with a source of volatile liquid. A zone of vapor supersaturation is thus created in which condensation on particles on the surface can occur. A light beam directed onto the surface scans the surface. Droplets are detected by means of light scattered from the droplets. In an alternate embodiment a stream of carrier gas may be provided around the wick or bubbled through a jar of volatile liquid to direct a vapor toward the test surface. In another embodiment, multiple wicks communicate with different sources of volatile liquids. In a method of the invention, mulitple scans are made with either different levels of vapor supersaturation or different vapor compositions.

Abstract: An apparatus for detecting submicron particles in air includes a saturator for saturating a sample stream of the air with a vapor of a low volatility liquid and a condenser for cooling the vapor to form droplets around the particles to result in particles of a size detectable by an optical detector. Conduits extend through a bath of the liquid in the saturator so that sample streams passing through the conduits are heated by the bath. A flow divider divides a single sample stream at the inlet of the saturator into a plurality of laminar flow streams corresponding in number to the conduits. The condenser is a heat exchanger having a plurality of tubes with funnel-shaped inlet ends positioned over the bath of the saturator, and the tubes are inclined toward their inlet end so that condensed vapor flows back into the bath.

Abstract: The present invention provides a device for the real time measurement of the content of an aerosol in a gas.The device performs the measurement on the basis of a sample of the gas and comprises enlargement means able to condense on the sampled aerosol, a vapor of a liquid, so as to obtain droplets of a solution of the aerosol in the liquid, impaction means, able to spray droplets onto a support provided for collecting at least one known fraction of these droplets, means for the continuous analysis of the thus collected droplets, said analysis means being specific to the aerosol the content of which is to be measured and able to supply information relative to said content and electronic means for processing the information and able to determine the content on the basis of said information.

Abstract: Method and apparatus for the measurement of sub-ppm concentrations of impurities in liquids. The liquid to be measured for impurities is dispersed into uniform droplets of a precisely known diameter D in a gas stream, such as air, using for example, a vibratory orifice generator. The dispersed droplets evaporate in the gas stream to leave a residue particle having a diameter d, which can be measured for example by means of a laser light scattering spectrometer. The concentration by volume, C.sub.v, of the impurities can then be calculated according to the equation; C.sub.v =(d/D).sup.3.

Abstract: A system for detection of extremely small particles in a low pressure environment or vacuum includes a vapor column in which a diffusion oil is vaporized, a saturation column in which vaporized oil is cooled and supersaturated, and means for directing a low pressure gas into the saturation column. An optical detector senses the oil droplets that grow around extremely small particles which are introduced in the saturation column by the gas and fall past the detector.

Abstract: A condensation nucleus counter (1) for measuring particulate concentration within a gaseous environment, including an inlet orifice (3) leading to a flow path (5) within saturator (4). The resultant vapor (10) enters a condenser section (11) wherein the particulate matter suspended within serves as the nucleus for condensation. The enlarged droplets (23) thus formed enter a conventional optical particle counter section (15).

Abstract: An improved incipient fire detector that employs a sub-micrometer size particle detector of the Wilson cloud chamber type in conjunction with a continuous on-the-fly sequential selector valve assembly and sample gas conduit system for monitoring a plurality of different enclosed spaces (zones). The sampling line for each zone can have up to ten heads, and delivers air or other gaseous atmosphere samples from the respective parts of the zone to the centrally located particle detector at a continuous flow rate of about 14 liters a minute. Each zone line is sampled sequentially by an electronically controlled selector valve assembly for a 15 second interval, once a minute. The cloud chamber particle detector operates at a cycling rate of about once per second and provides a continuous analog voltage corresponding to small particle concentration in the portions of the zone being sampled.

Abstract: A method and an apparatus for measuring an impurity concentration of a liquid comprises atomizing step for atomizing the objective liquid, e.g. pure water, having a predetermined droplet size distribution, and an evaporating step for evaporating to dryness the droplets so as to generate fine particles. Those particles are fed to a condensation nuclei counter, hereinafter referred to as CNC, which counts the number of fine particles and has a specified sensitivity characteristic curve. Then impurity concentration of the objective liquid can be measured, since the concentration is related to the counted number of the CNC, the distribution of droplet size of the atomizer, and the sensitivity characteristic of the CNC including the particle deposition loss.

Abstract: A method and apparatus for determining the dew point or dew point depression which is arranged for unattended operation and is extremely accurate in the vicinity of very small dew point depressions. In addition to measuring present dew point depression, historical records are maintained and the device is arranged to perform a time trend analysis so as to provide for short term future prediction. Output is provided via a voice synthesizer and a radio. Dew point depression is computed by determining the adiabatic change in volume required to produce condensation. The change in volume is produced by rapidly expanding a test chamber. The measurement cycle concludes with a compression step to raise chamber temperature to at least freezing.

Abstract: A method and a system for measuring the number of hyperfine particles comprising the step in which an air aerosol containing fine particles is led into a saturated vapor chamber and a high temperature saturated vapor chamber, respectively, to produce saturated vapor aerosols, the step in which the two saturated vapor aerosols produced as aforenoted are led into a mixing chamber, so that the aforementioned vapor is condensed on the aerosol particles as the nuclei, thereby achieving growth of the aforementioned fine particles, and the step for measuring the number of the said fine particles grown in that way.

Abstract: A portable device and a process for detection of persons and things by the Condensation Nuclei" technique. The disclosure sets out a new continuous flow device and process that collects an air sample, subjects it to supersaturation conditions when flowing for growing or condensation on air sample nuclei, and detects and counts the condensated or grown particles with a photo means and a conventional counter. An air sample is pumped through a heated tube humidifier where the sample becomes supersaturated for condensation. It is then carried by detector means for counting.

Abstract: The presence of red phosphorus in solid form is detected through the use of a condensation nuclei detector and the preliminary steps of reacting the phosphorus body with ozone and then removing solid particles from a sample of the resulting gas mixture and forming phosphoric acid nuclei in the filtered gas sample.

Abstract: A condensation nuclei counter for measurement of the concentrations of Aitken particles in gases by measurement of light scattered in a cloud chamber by water droplets formed on the particles in successive samples of a gas wherein the counter provides for sequential high speed sampling of the photodetector output during the cloud chamber growth of the droplets of each gas sample tested as a way of measuring the rate of increase of total droplet cross-section and wherein the counter provides for automatic ranging for particle population coordinated with the timed sampling during particle growth.

Abstract: A continuous HCl in-air indicator consists of a tube-like element with an inlet end through which a continuous stream of air, containing HCl, enters. The air flows downstream from the inlet end and exits the element's outlet end. Positioned between the element's inlet and outlet ends are first and second spaced apart photoelectric units, which are preferably positioned adjacent the inlet and outlet ends, respectively. Ammonia gas is injected into the air, flowing through the element, at a position between the two photoelectric units. The ammonia gas reacts with the HCl in the air to form ammonium chloride particles. The difference between the outputs of the two photoelectric units is an indication of the amount of HCl in the air stream.