Apparatus for measuring characteristics of particles in fluid by detecting light scattered at the particles

• US 4,957,363 A
• Filed: 07/01/1988
• Issued: 09/18/1990
• Est. Priority Date: 07/03/1987
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Ito, Yoshitoshi, Takeda, Kazuo
• Primary Examiner(s): McGraw, Vincent P.
• Application Number:
  US07/214,515
• Time in Patent Office: 809 Days
• Field of Search: 356/73, 356/336, 356/338, 356/339, 356/343, 356/72, 250/222.2
• US Class Current: 356/73
• CPC Class Codes: G01N 15/1427 with the synchronisation of components, a time gate for operation of components, or suppression of particle coincidences
• CPC Class Codes: G01N 15/1434 Optical arrangements
• CPC Class Codes: G01N 15/1459 the analysis being performed on a sample stream
• CPC Class Codes: G01N 2015/1486 Counting the particles
• CPC Class Codes: G01N 2015/1493 Particle size
• CPC Class Codes: G01N 21/53 within a flowing fluid, e.g. smoke

Abstract

In a particle measuring apparatus for measuring characteristics of particles by detecting light scattered at the particles while irradiating the particles in fluid with light, the scattered light is detected by means of a plurality of detectors and the characteristics of particles are determined by using pulse signals of detection signals coming from the plurality of detectors, which are coincident with each other.

Claims

1. A particle measurement apparatus comprising:

means for generating laser lights having wavelengths which are different from each other;

a flow cell through which a fluid sample including particles flows;

focusing means for collecting said laser lights and for irradiating said fluid sample therewith;

monochrometer means for wavelength-separating scattered light from said particles;

a plurality of detector means for detecting the wavelength-separated scattered light from said monochrometer means; and

measuring means for extracting output pulse signals of said plurality of detector means which are indicative of said particles and which are coincident with each other in timing of detection so as to enable measurement of the number, size and refractive index of said particles by use of said extracted output pulse signals of said plurality of detector means.

2. A particle measurement apparatus according to claim 1, wherein said monochrometer means includes a plurality of monochrometers.

3. A particle measurement apparatus according to claim 1, wherein said measuring means includes a memory for storing said extracted output pulse signals.

4. A particle measurement apparatus comprising:

means for generating laser lights having wavelengths which are different from each other;

a flow cell through which a fluid sample including particles flows;

focusing means for collected said laser lights and for irradiating said fluid sample therewith;

a plurality of monochrometer means each of which wavelength-separates scattered light from said particles;

a plurality of polarization dividing means associated with said plurality of monochrometer means for receiving the wavelength separated scattered light from the associated monochrometer means so that said plurality of polarization dividing means divides the received wavelength-separated scattered light into different polarized components;

a plurality of detector means for detecting the different polarized components from said plurality of polarization dividing means; and

measuring means for extracting output pulse signals of said plurality of detector means which are indicative of said particles and which are coincident with each other in timing of detection so as to enable measurement of characteristics of said particles.

5. A particle measurement apparatus according to claim 4, wherein each of said plurality of polarization dividing means includes a plurality of polarizers for the associated monochrometer means, each of said plurality of polarizers dividing the wavelength-separated scattered light from the associated monochrometer means into different polarized components.