KR0125916B1 - Portable particle analyzers - Google Patents

Abstract

none

Description

Handheld particle analyzer

1 is a cross-sectional side view of a preferred embodiment of the present invention,

1A is a cross-sectional view taken along the line of FIG. 1,

2 is a side cross-sectional view of another embodiment of the present invention,

3 is a side cross-sectional view of an additional embodiment of the present invention.

The present invention relates to a fluid borne particle analyzer. For example, in the study of aerosel, aerosol diffusion, and airborne particle contamination control, it is necessary to know the geometry and symmetry of each particle, as well as to quickly determine the particle size distribution on the order of 1 to 10 microns in diameter. .

In particular, the information on the geometric shape and size distribution of each particle makes it possible to identify, for example, spherical symmetric particles and to count or monitor droplets of droplets in an environment containing other solid non-spherical particles. . The term particles in this specification is used in the sense that it applies to both solids and liquids.

The device should be able to count each particle in the sample at a rate of 20,000 per second, distinguish between spherical and non-spherical particles, and count each shape. Another desirable property is to classify spherical particles with a low micron diameter into multiple size bands, and to classify non-spherical particles with respect to this classification, so that the non-spherical particles within the size spectrum under the overall condition that the particles are spherical. Ignore it.

Conventional techniques for testing particles using several commercially available instruments use electromagnetic radiation analyzers and detectors that are scattered by the particles. All of these instruments use mechanical mechanisms to drive the sample air through a sensing volume, where the transported particles are illuminated by incident electromagnetic radiation. The radiation scattered by the particles is received by one or more detectors that convert energy into electrical signals, and information from these electrical signals can be extracted by appropriate electrical circuits.

Particle analyzers are known, for example, described in British Patent Application Nos. 8,619,050, 2,041,516A, 2,044,951A and US Pat. No. 3,946,239. The analyzers include concave reflectors in a scatter chamber and sample fluid flow blocked by the radiation beam. Light scattered from individual particles in the fluid is directed to the radiation collector by the reflector and analyzed continuously.

But all of this is cumbersome and brittle, and therefore not portable. Moreover, light scattered at low angles from the particles in the sample is not detected by any of the prior art systems described above.

Thus, a compact, portable, particle analyzer that determines the particle size, geometry, and number in the sample fluid is needed, and the ability to detect and analyze light scattered at low angles from individual particles in the sample. Must be added.

According to one feature of the invention, the particle analyzer comprises a first scatter chamber, means for providing a distilled fluid sample through the first scatter chamber, and at least one radiation scattered by each particle in the sample. A radiation beam adapted to block said sample at right angles to the direction of flow at the focal point of the first concave reflector used to direct towards the first reflector radiation collector, and means for converting the collected radiation into electrical signals for processing and analysis. And means for dumping non-scattered radiation.

A laser mounted to any one of the plurality of passages provides a beam of radiation at right angles to the sample beam. The radiation beam is arranged in alignment with the main axis of the first concave reflector, for example, and the arrangement makes the device more robust and more compact.

The first concave reflector is a parabolic mirror or an elliptical mirror, which reflects the scattered light to a single detection point.

The advantage of having a second chamber coaxially with the first chamber is that it can detect and analyze light scattered at low angles from the individual particles in the sample. This information is especially used to determine particle size. The second chamber may or may not include a second concave reflector. If the second concave reflector is not used, the second chamber has a radiation collector installed around a beam that is scattered, for example, in a concentric ring. If a second concave reflector is used, the reflector is an elliptical mirror and preferably has a radiation collector located at near and far focus at the beam and sample interception points. Thus, the light scattered at a low angle is reflected by the ellipsoid mirror to the near focus and collected by the radiation collector.

Any suitable type of radiation collector may be used in the present invention, which may include a photo multiplier unit, which, due to the optical fiber, causes the photo multiplier unit or lens to direct radiation to the photo multiplier or optical fiber. do.

According to a second aspect of the invention, a particle analysis method comprises passing a laminar flow fluid sample through a first scattering chamber and focusing the first concave reflector used to direct radiation towards one or more first reflector radiation collectors. Passing a beam of radiation through the first scattering chamber to block the sample at right angles to the flow direction at the second recess, wherein the low angle scattered radiation is arranged such that its far focus is at the beam beam and the blocking point of the sample Passing through a hole in the second concave reflector into a second room having a reflector and a second reflector radiation collector positioned at a near focal point of the second concave reflector, converting the collected radiation into an electrical signal; Processing and analyzing the electrical signal and dumping non-scattered radiation.

The sample is aerosol.

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

As shown in FIG. 1, the first scattering chamber 10 includes a first concave reflector in the form of a parabolic mirror 11, a lens 12, and a radiation collector 13. The laser 14 is installed in alignment with the main axis of the parabolic mirror 11, directs the radiation beam 15 to the focal point of the parabolic mirror 11, and the laminar flow of sample fluid in the parabolic mirror is blocked. The hole 18 leads to a second chamber 19, which has a second concave reflector in the form of an ellipsoid reflector 20 and a radiation collector 21 located at a near focus of the ellipsoid reflector 20. The ellipsoidal reflector is positioned such that its far focal point is seated at the focal point 16 of the first parabolic reflector 11. A beam dump 22, typically a Rayleigh horn, is placed in a hole in the elliptical mirror 20 to collect scattered radiation. The radiation collectors 13, 21 are connected to the photomultiplier tube 23. 1A shows a possible radiation collector alignment around the laser 14. Although only three collectors are shown in FIG. 1A, multiple detectors may be placed radially around the laser 14.

2 shows another embodiment of the present invention, in which the laser 14, the elliptical reflector 40 is installed at an angle of 90 [deg.] With the major axis of the first concave reflector. A 45 ° mirror 41 is provided on the main axis of the reflector 40 and is used to direct the laser beam 15 along the main axis and toward the hole 18 in the ellipsoidal reflector 40. In practice, the laser 14 can be installed anywhere around the first scattering chamber 10 with the mirror 41 installed at an appropriate angle on the axis. The laminar flow fluid sample 17 is directed perpendicular to the paper to intersect the beam 15 at the focal point 16 of the ellipsoidal reflector 40. The collecting lens 12 directs the scattered light towards the radiation collector 13 which is connected to the photomultiplier tube 43 via the optical fiber 42. The second chamber 19 is non-reflective and has a plurality of optical fibers 43 arranged around the beam 15 and connected to the photomultiplier tube 23. The optical fiber 43 is arranged in a concentric ring around the beam 15.

Additional embodiments of the invention are shown in FIG. In a further embodiment, both the first reflecting mirror 50 and the second reflecting mirror 51 are elliptical mirrors. The laser 14 is at an angle of 90 ° with respect to the main axis of the reflector, so that the mirror 41 directs the beam 15 on the main axis. The sample 17 is directed perpendicular to the laser beam 15 and blocks the laser beam at the near focus 16 of the first ellipsoidal reflector 50. The second ellipsoidal reflector 51 is positioned to coincide with the far focal point 16. The photo multiplier tube 23 is placed at the far focus of the first ellipsoidal reflector and the near focus of the second ellipsoidal reflector 20 to collect scattered radiation. A beam dump 22 is placed in the second scattering chamber 19 to dump non-scattered radiation.

The radiation collector 23 shown in FIG. 3 is located facing the hole 18 in the first chamber 10 as opposed to being disposed at 90 ° to the direction shown in FIG. The alignment collects radiation of extremely low angular deflection but is reduced overall because it records deflections only in the direction of the collector plane.

The fluid sample 17, shown for example in FIGS. 1 and 3, is supplied in laminar flow by means of a sheath of constant velocity air supplied around the sample. This is to ensure that the outer portion of the sample fluid has the same velocity as the inner portion. Otherwise the outer portion of the sample will flow more slowly due to static friction with the air following the sample flow. In addition, the coaxial tube that supplies the sheath of air is designed to dynamically focus the particles in the sample to provide laminar flow of the particles. The laser beam 15 blocks the flow of the fluid 17 at right angles and light is scattered from the individual particles contained in the fluid. Scattered radiation is reflected away from the wall of the first concave reflector in the first scattering chamber 10. If the first concave reflector is a parabolic mirror 11 (FIG. 1), the radiation is reflected parallel to the principal axis; if it is an elliptical mirror 45, 50 (FIGS. 2 and 4) the radiation is the far focal point of the mirror. Headed to. This deflected radiation is then directed toward the photomultiplier tube 23 by directing the lens 12 as in FIG. 3 or as in FIG. 1, or as shown in FIG. 42 is used to face the photomultiplier unit 23.

The radiation scattered at a low angle by the particles is collected in a second chamber 19, which has an ellipsoid mirror 20 and a radiation collector in FIGS. It may be the photo multiplier tube 23 shown in the figure or the lens 21 of FIG. 1 leading to the tube. Alternatively, the second chamber may not have a reflector, in which case the scattered radiation is collected by the optical fiber 43 surrounding the non-scattered beam 15. Any non-scattered radiation is dumped by a beam dump 22, usually a Rayleigh horn.

All the radiation collected is then converted into electrical signals, processed and analyzed, and the information is extracted by appropriate electrical circuits.

Although the present invention has been described with reference to the accompanying drawings and examples, it can be said that modifications and improvements can be made without departing from the scope of the invention as defined by the claims.

Claims (2)

Means for providing a first scatter chamber (10), a laminar flow fluid sample (17) through the first scatter chamber, and one or more first reflector radiation collectors wherein the radiation scattered by each particle in the sample Treatment and analysis of the radiation beam 15 and the radiation collected, which block the sample 17 at right angles to the direction of flow at the focal point of the first concave reflector 11 used to direct toward (13). A particle analyzer comprising means for converting into an electrical signal (23) and means (22) for non-scattered radiation dumping, the holes 18 in the first concave reflector (11). The bi-scattering chamber 19 includes a second concave reflector 20 having a second reflector radiation collector 21 positioned at its near focus and positioned at its near focal point at the cutoff point of the radiation beam and the sample. The second reflector radiation collector 21 collects the radiation And means (23) for converting the signal into an electrical signal for processing and analysis. A particle analysis method comprising: passing a laminar flow fluid sample (17) through a first scatter chamber (10) and a first concave reflector used to direct radiation toward one or more first reflector radiation collectors (13). Passing the radiation beam 15 through the first scattering chamber to block the sample 17 at right angles to the flow direction at the focal point 16 of 11), and the low angle scattered radiation, the radiation beam 15 and A second chamber having a third concave reflector 20 arranged so as to have a far focal point at a cutoff point of the sample 17 and a second reflector radiation collector 21 positioned at a near focal point of the second concave reflector ( 19) passing through the hole 18 in the first concave reflector 11, converting the collected radiation into an electrical signal 23, processing and analyzing the electrical signal, and scattering non-scattered radiation. Dumping 23; Particle analysis method.

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