The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 03, 1990
Filed:
Jul. 28, 1987
Trent A Poole, Amherst, MA (US);
Norman C Ford, Amherst, MA (US);
Amherst Process Instruments, Inc., Amherst, MA (US);
Abstract
Apparatus, intended primarily for use in an aerodynamic particle sizing system, for generating a pair of closely-spaced, substantially parallel light beams and for determining particle sizes by measuring the times of flight of particles between the two light beams. The apparatus for generating the light beams includes a laser source, an aperture slit for establishing the shape of the beams, a cylindrical lens for focusing the laser beam on the aperture slit, a diffraction grating for converting the beam from the aperture slit into diffracted beams in the zero order lobe and one first order lobe and a transfer lens for directing the diffracted beams as substantially parallel beams. The particle measuring apparatus includes a prism, a lens arrangement for imaging light scattered by particles passing through one beam on a first face of the prism and for imaging light scattered by particles passing through the other beam on a second face of the prism that is perpendicular to the first face, and a pair of photomultiplier tubes for detecting light reflected by the faces of the prism. Start and stop pulses from the photomultiplier tubes are processed to determine particle time-of-flight which is then converted to particle size.