KR0125917B1 - Particle asymmetry analysis - Google Patents

Abstract

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Description

Asymmetric particle analyzer

1 is a schematic side view of a cross section of a particle analyzer that breaks down spherical particles.

2 is a cross-sectional view of the analyzer taken along the X-X line of FIG.

3 is a schematic side view of a cross section of an asymmetric analysis system.

The present invention relates to the analysis of fluid borne pontiles, and in particular to techniques for considering the asymmetry of such particles. For example, in the study of aerosol, aerosol diffusion, and airborne particle contamination control, there is a need to quickly determine particle size classifications on the order of 1 to 10 microns in diameter, together with some known geometry and symmetry of individual particles. have. The information can, for example, identify particles that are spherical symmetric, allowing counter / monitor operation of droplets of liquid in an environment containing other solids that are non-spherical particles. In the present specification, the particles apply both to the solid and to the drop of the liquid.

The technique must be able to distinguish between spherical and non-spherical particles in the sample and be able to count individual particles in the sample at a typical rate of 20,000 particles per second, each type of countable. It also classifies into a number of size bands of spherical particles having a diameter of 0.5 to 15 microns, and also classifies particles that conform to non-spherical shapes in connection with this classification, ignoring particles in the size spectrum.

Conventional techniques for particle testing using several commercially available instruments use electromagnetic radiation analyzers and detectors scattered by particles. All of these instruments use mechanical mechanisms to drive the sample air through the sensing volume where the carried particles are illuminated by incident electromagnetic radiation. The radiation scattered by the particles is received by one or more detectors from which energy is converted into electrical signals from which information can be leaked by a suitable electrical circuit.

A first class of commercially acceptable instruments allows for the simultaneous acceptance of scattered radiation from a large amount of particles and determining the average or statistical mean size of the particle body suitable for the particulate mass of a unit volume of gas or air. Use information. These instruments cannot be used to test individual particles and therefore cannot calculate information about particle morphology or accurate particle counts.

The second class of mechanisms utilizes laminar flow characteristics in gas to confine particles to smaller sensing volumes, focusing incident electromagnetic radiation in any manner, counting particles, and approximating the size of individual particles. You can do a test.

Thus, while conventional instruments can provide information to some extent on particle size and particle count, no instrument is available that can give information about the asymmetry of individual fluid producing particles.

Accordingly, there is a need for particle analyzers that can analyze individual fluid generating particles and provide information about the asymmetry of the particles, for example, by discretizing asymmetric elements into individual particles.

According to one aspect of the invention, there is provided a means for releasing a fluid sample in the form of a laminar fluid, means for illuminating said sample with a radiation beam, means for radiating and directing scattered radiation to a photocollector, and particles. Particle analyzers are provided that comprise means for extracting data from a photocollector and means for comparing the data with known forms of data to determine the degree of particle asymmetry.

The radiation beam is preferably provided by a laser and the scattered radiation is reflected by a concave reflector, which is preferably an elliptical mirror with the radiation directed towards the radiation collector. The scattered radiation at a low angle is detected in the second scattering chamber, from the hole in the elliptical mirror, by the radiation collector, to guide the optically centrally aligned optical fiber around the non-scattered beam. The collected radiation is then converted into an electrical signal, processed, analyzed, and the particles become asymmetrical elements compared to data in the form of known particles.

Furthermore, in addition to the asymmetrical element, the particle size can also be determined. The result of this accumulation of motion, which can be a large number of particles as an asymmetric element and combined with a spectrum of correlated sizes, results in a particle print in the environment in which the value is more than the data taking only a single particle. Used to generate

Looking at the spherical shape, the spherical particle classification criteria are easily defined as symmetrical scattering about the axis of the illumination beam of radiation that is optionally flattened or circularly flattened. Therefore, the plurality of radiation collectors are radially symmetrical with respect to the reflection axis of the concave reflector.

The degree of asymmetry does not suggest that the collector alignment is optimal for particle asymmetry analysis. The design of the scattering chamber must allow for the flexibility of the specifically required collector structure and the location of the arbitrarily varying positions.

The advance in this technique is that, unlike mechanically extremely difficult tests, it is easy to simulate the performance of positioning most collectors at any location around most of the scattering range using optical fiber collection optics. Thus, with high flexibility, various detection geometries can be tested without the need for mechanical changes to the scattering chamber itself.

According to a second aspect of the invention, a method of determining asymmetry of a fluid producing particle; Providing a fluid sample in laminar flow form; Illuminating the sample with a radiation beam; Reflecting the radiation scattered by the individual particles to a radiation collector; Extracting data from a light collector that describes the particles; Comparing the data with known types of data to determine the degree of particle asymmetry.

The sample is an aerosol.

Two embodiments of the present invention will be described below with reference to the accompanying drawings, for example.

FIG. 1 shows the basic form of the present invention in which only spherical particles are analyzed and located at one end of the scattering chamber 2 of the parabolic concave reflector 1. A scattering chamber 2 at the major axis of the reflector and a laser 3 directed towards the radiation beam 4 towards the hole 5 in the reflector 1 are mounted at the other end of the scattering chamber 2 and the reflector 1 ) Is aligned to the major axis. After passing through the hole 5, the beam 4 enters the beam dump 6, which is typically a Rayleigh horn.

The sample 7 of laminar air is directed into the scattering chamber 2 to block the laser beam 4 at a right angle at the focus of the parabolic reflector 1.

The particles of the sample 7 deflect radiation from the beam 4 towards the reflector 1 which reflects parallel to the main axis towards the radiation collector 8 adjacent to the laser 3. The radiation collector 8 may be a photo multiplier unit, an optical fiber leading to the unit, or a lens for directing light to a fiber or unit.

As shown in FIG. 2, three radiation collectors 8 are arranged radially around the beam 4. In these phrases, symmetrical scattering is oriented to identify spherical particles. In practice, a plurality of radiation collectors 8 can be arranged radially relative to the radiation beam 4.

3 shows a preferred embodiment of a particle analyzer according to the invention which can decompose particles individually, so that they belong to an asymmetrical element. In this embodiment, the laser 3 is mounted below the scattering chamber 2 with the reflector 1 at 90 ° with respect to the main axis. The beam 4 is reflected on the major axis of the reflector by means of a mirror or mirror 9 properly positioned on the axis. In practice, the laser 3 is mounted directly at any place with respect to the scattering chamber 2 with the mirror 90 at an appropriate angle on the axis.

FIG. 3 also shows an ellipsoidal reflector 10 having a blocking point between the sample 7 and the beam 4, which is a focal point of the ellipsoid, and the radiation collector 8 at the end of the scattering chamber 2 with the reflected radiation. A scattering chamber 2 is shown having a collector lens 11 mounted adjacent to a second focal point parallel to. In this respect, the intensity distribution represents a spatially altered replication scattered into the sphere of approximately 0.84 by the particles. The figure shows a sample 7 of fluid delivered to laminar flow by a sheath air inlet 12 which supplies an air layer at a constant rate.

It is known from experience that there are many difficulties in capturing and analyzing scattered radiation at low angles to the beam 4 direction. At extremely small angles (1 ° to 3 °), they are sunk by the light scattered from the sustained focus light. In order to solve this problem, the second scattering chamber 13 is introduced coaxially with the main axis of the concave reflector 1 on the main scattering chamber 2. The radiation collector 8 is suitably positioned in the scattering chamber to collect low angle polarizations.

3 shows a second scattering chamber 13 in which an optical fiber 14 is arranged around the beam 4. The optical fiber 14 is disposed at a concentric rim around the beam 4. The optical fiber 14 acts as a radiation collector for converting the collected radiation into electrical signals for processing and analysis.

As shown in FIG. 1, the second scattering chamber 13 has the intersection of the radiation collector 15 at the first or near focus, the sample 7 as the second or far focus and the beam 4. It may have a second concave reflector 14 which is a vertical ellipsoid. The radiation that is deflected at a low angle thus hits the elliptical reflector and is directed to the radiation collector 15.

The radiation collector 15 may be positioned at 90 ° with respect to this direction as shown in FIG. 1 or may be positioned to face the hole 5 on the first scattering chamber. The 90 ° arrangement can collect much more radiation of low angle deflection, but overall less because deflection is recorded only in the opposite direction of the collector.

1 illustrates a method of using a sample 7 which is supplied in laminar flow by a constant velocity filtered air sheath means that is supplied around the sample. The outside of the sample flows at the same speed as the inside. The outside of the sample flows more slowly, due to friction with stagnant air behind the sample flow. More importantly, coaxial tubes supplying air for the sheath are designed to dynamically focus the particles on the sample to provide laminar flow of the particles. Thus, the particle flow on the focus of the reflector becomes easy to align in a line.

The asymmetric particle analyzer works as follows. The laser beam produced by the gas laser enters the scattering chamber at right angles to the major axis of the reflector and is reflected at 90 ° along the major axis of the reflector. Thus, radiation scattered by individual particles at approximately 19 ° to 145 ° with respect to the beam axis is reflected into the non-spherical collection lens at the rear of the scattering chamber. Such lenses exhibit spatially altered replicators where the incoming light is parallel and the intensity distribution across the output window is scattered within approximately 0.84 of the sphere by the particles.

The position of the optical fiber detector for measuring light distribution with the collected light of the above-described type can be changed as necessary.

The detector is arranged symmetrically about the axis of the output window to determine spherical particles.

With the use of fiber optic lenses the effect of placing multiple detectors at any location surrounding most of the scattering spheres is easily tested.

Based on the experimental results of the scattered form of the scattered form and the results of the theoretical model, asymmetrical elements are used in the computation of the particles.

The processing of data from particles that determine asymmetry is coordinated by, for example, a transporter produced by the British Inmos chip manufacturers.

One computer is used for each detection channel. In this way, tests performed by taking data in-line from a channel are performed on all channels that simultaneously provide a general increase in material processing data.

Although the present invention has been described with reference to the above-described preferred embodiments, the present invention is capable of other changes without departing from the invention as defined by the claims.

Claims (2)

Means for providing a sample (7) of covalent suspended particles in laminar flow, a means (3) for illuminating said sample with a laser beam, and radiation scattered by the individual particles to a radiation collector (8, 15) Means for directing three or more predetermined backward directions 1 and one predetermined forward direction 16 toward the side, and means 20 incorporated in each collector 8, 15 for detecting the radiation collected thereby; 21) and particle symmetry including means for extracting data from a detector to describe the particles, and means for comparing the data from particles of known type to determine the degree of symmetry of the individual particles. In the particle analyzer for measurement, the structure of the radiation collectors 8 and 15 can be freely modified to allow the collection of scattered radiation at different predetermined angles. Stoneware. Providing a sample (7) of air suspended particles in laminar flow form; The sample is illuminated with a laser beam 4 and reflects the radiation scattered by the individual particles to one or more forward scattering collectors 15 and three or more backward scattering collectors 8, so that each collector 8 Detecting radiation collected by (15); Leaking data that discscribes the particles from the detected radiation; In a particle symmetry method comprising comparing the data with a known type of data to determine particle symmetry, the structure of the radiation collector is freely modified to allow the collection of scattered radiation at different angles. Method for measuring particle symmetry, characterized in that.

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