Commissariat a L'energie Atomique

Commissariat &#xc0; L'&#xc9;nergie Atomique Et Aux &#xc9;nergies Alternatives

Michel Pourprix

Simon Clavaguera

Denis Boulaud

Francois Tardif

Arnaud Guiot

Patrick Burghoffer

Christophe Brouard

Philippe Mulcey

Nicolas Daniel

François Tardif

Quentin Renot

Guy Madelaine

Patrick Poussier

Patrick Pybot

Jacques Vendel

The invention consists of a continuous sorting method and device which highlights the trajectory differences to which fibers of different form factors and particles charged under the joint influence of electrical forces and a centrifugal force could be subjected. Thus, according to the sorting method, the conditions exploit this difference in order to recover/collect the fibers separated from the non-fibrous particles present in the same initial aerosol or to sort fibers exhibiting different form factors.

Method and device for sorting fibers in suspension in an aerosol through the combination of electrostatic and centrifugal forces

The invention relates to a method and device for collecting particles which may be present in an aerosol. The invention consists in electrostatically collecting all the particles in an aerosol, but uncoupling mechanisms of particle charging by unipolar ion diffusion, for charging then collecting the finest particles, from particle charging by a corona effect electrical field, for charging then collecting the biggest particles in a different collection zone from the collection zone for the finest particles. The invention also relates to the use of such a device as ionisation chamber or for evaluating the exposure of workers or consumers to nanoparticles.

Selective aerosol particle collecting method and device, according to particle size

The invention relates to a method for the selective purification of aerosols. The invention consists in electrostatically collecting all of the particles present in an aerosol, but with separation of the mechanisms on one hand for charging particles by unipolar ion diffusion in order to charge and then collect the finest particles, and on the other hand for charging particles by means of Corona discharge in order to charge and then collect the largest particles on a substrate different from the substrate for collecting the finest particles.

Method for the selective purification of aerosols

The invention relates to a method and device for collecting nanoparticles which may be present in an aerosol. The invention consists of electrostatically collecting nanoparticles contained in an aerosol by a mechanism of particle charging by unipolar ion diffusion, followed by the application of a field without a corona effect, which makes it possible to deposit the particles in concentric rings on different parts of a single flat substrate oriented orthogonally to the aerosol circulation direction. The biggest particles are deposited towards the centre of the flat substrate and the finest particles towards the periphery of the flat substrate. The invention also relates to a method of operation and to the use of such a device for evaluating the exposure of workers or consumers to nanoparticles.

Device for collecting particles contained in an aerosol, comprising electrometres to determine nanoparticle concentration and particle size

A charged particle selector having first and second circular electrical mobility selector portions is shown to include directing portions for directing particles selected by the first circular electrical mobility selector to the input of the second circular electrical mobility selector. These selectors may be combined to be in parallel instead of in series. The charged particle selector can be used to make in-line measurement of the mass and/or density of aerosol particles, to make measurements of the size of the particles and/or their distribution as well as the distribution of aerosol electrical charges.

Charged particle selector as a function of particle electrical mobility

The invention concerns a dynamic particle mobility selector comprising two separate and parallel coaxial disks (30, 32) defining a dynamic selection zone (31), the upper disk comprising an annular slit with radius r.sub.1 and a central suction intake (38) in order to circulate a laminar, centripetal and stable air flow in the dynamic selection zone. An annular opening (36) with average radius r.sub.2 &lt;r.sub.1 may be provided in the lower disk (32). Application to a dynamic mobility spectrometer, to a device for measuring the particle size of an aerosol and a mono-dispersed aerosol generator.

Dynamic mobility selector for aerosol particles

The electrostatic selector of aerosol particles of an atmosphere has a first (18) and a second (20) spaced, parallel, coaxial conductive disks between which is established an electrical field, an annular slot (22) made in the first disk in order to communicate with the atmosphere to be examined, a central intake (26) for bringing about a circulation from the periphery of the disks of a stable, centripetal, laminar filtered air flow, the second disk (20) having a central extraction orifice (28).

Charged particle selector

An electrical mobility spectrometer for aerosol particles of an atmosphere to be examined comprises a first (18) and a second (20), spaced, parallel, coaxial conductive disks between which is established an electric field, an annular slot (22) formed in the first disk for communicating with the atmosphere to be examined, a central intake (26) for bringing about a circulation from the periphery of the disks of a centripetal, stable, laminar filtered air flow, an annular slot (28) made in the second disk, a device for varying the selected electrical mobility and an aerosol detector or collector (17).

Particle, particularly submicron particle spectrometer

This electrostatic selector of aerosol particles of an atmosphere has a first (18) and a second (20) parallel, spaced, coaxial conductive disks, between which is established an electric field, an annular slot (22) made in the first disk for communicating with the atmosphere to be examined, a central intake (26) for bringing about a circulation from the periphery of the disks of a stable, centripetal, laminar filtered air flow, an annular or circular opening (28) made in the second disk, a third disk (32) facing the second disk, means for injecting between the second and third disk, from the periphery thereof, a radial, laminar, filtered air flow, a central pipe fixed to the third disk by which the particles having the requisite electrical mobility (or the requisite dimension if the electric charge is known) are brought to the outside of the apparatus.

Electrical mobility selector of charged particles

A process and apparatus for calibrating a particle counter is described. The process comprises the steps of forming a vector gas flow by an aerosol of particles of the same grain size, developing ions in the vector gas with both sign by a bipolar charger, certain particles being electrically charged to a stationary charge state in which the distribution of the number of charges fixed to each particle follows a Gaussian law (Gunn or Boltzmann), passing the charge aerosol into a mobility selector to attract the charged particles to electrodes therein and classify them as a function of the numbers p of their elementary electrical charges e and allowing the electically neutral particles to escape, collecting the neutral particles and passing the neutral particles into the particle counter to be calibrated, the particles counter displaying a value N'.sub.o ; counting the values of N.sub.p and N.sub.p+1 of the number of particles of charges pe and (P+1)e fixed by the selector and calculating by the formula ##EQU1## the number N.sub.o representing the number of neutral particles supplied to the counter and comparing N'.sub.o with N.sub.p. An apparatus using above process to separately pick-up the charged particles with a view to count the numbers N.sub.p and N.sub.p+1 contains a particle counter in which particles of the same grain size are produced comprising a cylindrical case containing an annular cylindrical bipolar charge space and a mobility selector linked with the charge space and are superimposed manner within the cylindrical case.

Process and apparatus for calibrating a particle counter

Electrostatic detector according to claim 2, characterized in that it is constituted by a flattened circular cylindrical case (2) having two axial pipes, one for injecting a gas (4) into the lower part of the case and the other for extracting the gas (8) in the upper part of said case, the latter being provided on its upper periphery with an annular slot (12) for the entry of the atmosphere to be analyzed and, in its center, a solid thick disk (14), whose upper face supports one of the two conductive disks (16), the second conductive disk (18) being constituted by the upper cover of the case, the injection gas flow passing round the thick disk after passing through a filter (20) for the purification and uniform distribution of its flow.

Electrostatic detector of aerosol particles

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.

Device for the real time measurement of the content of an aerosol in a

An apparatus of the aerosol sampler type with cascade impaction and uniform deposition comprising a conical air inlet fixed to a tight, hollow, cylindrical chamber of revolution constituted by the superimposing of several stages in the form of hollow cylinders of revolution traversed by the air flow from the conical inlet and each having a circular plate perforated with holes located on concentric circles coaxial to the plate and having an identical diameter progressively decreasing in each stage, as well as a collection disk located downstream of the perforated plate and whose diameter is smaller than the internal diameter of the impacter chamber, incorporating a pump for ensuring the vertical downward circulation of the air and driving gears for the relative rotation of each perforated plate with respect to the corresponding collection disk, wherein in each stage the axis of rotation of the disk passes through the disk and is offset relative to the axis of the circular perforated plate.

Aerosol sampler with cascade impaction and uniform deposition

Device for analyzing the activity of a radioactive aerosol as a function of the grain size distribution of its particles of the type comprising a tight enclosure, means for circulating the aerosol through said enclosure and within the latter, a plurality of stages for collecting aerosol particles with a given grain size, each of the stages comprising an aerosol injection plate perforated by at least one calibrated opening and a collection plate for particles of a given grain size, wherein it comprises means for establishing an electric field between the injection and collection plates of each of the stages with a view to establishing an ionization current through a stage during the disintegration of the particles collected in the latter and means for measuring the ionization current of one of the said stages.

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Montlhery, France

Michel Pourprix