Particle evaluator

Claim 2

In apparatus for evaluating particles having a light transmitter for transmitting radiation as a beam along an optical axis to a sample zone; and optical means for transmitting radiation from an object plane in said sample zone along said optical axis and for focusing at a picture plane images of particles at said object plane said optical means rendering said object plane conjugate with respect to said picture plane, whereby images of particles simultaneously present at said object plane are sharply defined as separate images in said picture plane; the improvement that comprises: means for directing a stream of said particles into said sample zone along a path transverse to said optical axis whereby separate particles may be present there simultaneously; and wall means having apertures aligned with said optical axis on opposite sides of said sample zone for confining the flow of said stream to a narrow region at said object plane.

Claim 3

In an apparatus for evaluating particles, as defined in claim 1, means for displaying a visible areal image of the particle images formed in said picture plane.

Claim 4

In an apparatus for evaluating particles, as defined in claim 1, means for recording signals representative of an areal image formed in said picture plane.

Claim 5

In an apparatus for evaluating particles, as defined in claim 3, a viewing screen, means for reproducing on said viewing screen said signals as a visible areal image of the particle images formed in said picture plane, and means on said viewing screen for measuring the sizes of the particles imaged thereon

Claim 6

In apparatus for evaluating particles as defined in claim 1, wherein said light transmitter comprises means for supplying a collimated laser beam and a condensing lens for condensing said collimated laser beam at a focal area on the upbeam side of said object plane and adjacent said sample zone.

Claim 7

In apparatus for evaluating particles as defined in claim 1, wherein said light transmitter comprises means for supplying a laser beam to said sample zone, wherein said optical means comprises an apertured mirror for deflecting radiation from said sample zone to said picture plane, and means for imaging said laser beam at the aperture of said mirror to reduce the amount of the said beam that is not scattered by such particles from falling upon said picture plane.

Claim 8

In apparatus for evaluating particles as defined in claim 1, in which said wall means comprises first and second convex members having small coaxial apertures that provide said openings on opposite sides of said sample zone, the wall of said first convex member diverging away from said optical axis on the upbeam side of said sample zone and the wall of said second convex member diverging away from said optical axis on the downbeam side of said sample zone.

Claim 9

In apparatus for evaluating particles as defined in claim 1, in which said wall means comprises first and second cones arranged coaxially with said optical axis, said cones having said apertures at their tips and said cones being arranged with their apertured tips adjacent each other on opposite sides of said sample zone with the wall of said first cone diverging away from said optical axis on the upbeam side of said sample zone and with the wall of said second cone diverging away from said optical axis on the downbeam side of said sample zone.

Claim 10

In apparatus for evaluating particles as defined in claim 8, and comprising a tubular light-proof, gas-leak-proof tubular member embracing the space between said first cone and the space in which said collimated laser beam is transmitted, and a second light-proof, gas-leak-proof tubular member embracing the space between the second cone and said picture plane.

Claim 11

In apparatus for evaluating particles as defined in claim 7, comprising means for supplying gas under pressure to the space within said convex members and forcing air to flow gently into said sample zone while still permitting the stream of particles to flow through said sample zone from one side of said optical axis to the other.

Claim 12

In apparatus for evaluating particles as defined in claim 5, comprising means for adjusting the spacing of said condensing lens relative to said object plane along said optical axis.

Claim 13

In a method of evaluating particles, the steps that comprise: establishing an optical axis; establishing a sample zone at a position along said axis; establishing an image plane that is transverse to said optical axis; establishing in said sample zone an object plane that is transverse to said optical axis; optically conjugating said object plane with respect to said image plane by positioning optical elements between said planes whereby particles at said object plane are brought to a sharp focus in said image plane; transmitting a beam of radiation along said optical axis towards said sample zone; directing a stream of said particles into said sample zone along a path transverse to said optical axis; and interposing on opposite sides of said sample zone two walls having openings therein with said optical axis passing through said openings, thereby restricting the direct flow of said stream to a narrow region that includes said object plane thereby largely confining the paths of travel of particles to a region approximating the depth of focus at the object plane, whereby the images of such particles are focused on said image plane with little interference from out-of-focus images of particles outside said narrow region and movement of particles out of said sample zone along said optical path is impeded; whereby images of particles at said object plane are sharply defined in said image plane.

Claim 14

In a method of evaluating particles, the steps that comprise: establishing an optical axis; establishing a sample zone at a position along said axis; establishing an image plane that is transverse to said optical axis; establishing in said sample zone an object plane that is transverse to said optical axis; optically conjugating said object plane with respect to said image plane by positioning optical elements between said planes whereby particles at said object plane are brought to a sharp focus in said image plane; transmitting a beam of radiation along said optical axis towards said sample zone; directing a stream of said particles into said sample zone along a path transverse to said optical axis; and interposing on opposite sides of said sample zone two walls having openings therein with said optical axis passing through said openings, thereby restricting the direct flow of said stream to a narrow region that includes said object plane thereby largely confining the paths of travel of particles to a region approximating the depth of focus at the object plane, whereby the images of such particles are focused on said image plane with little interference from out-of-focus images of particles outside said narrow region and movement of particles out of said sample zone along said optical path is impeded; whereby images of particles at said object plane are sharply defined in said image plane.

Claim 15

In a method of evaluating particles as defined in claim 12, including the steps of: developing electric signals representative of the areal distribution of light in said image plane; utilizing said electrical signals to form on a viewing screen, a visible image of the images formed in said image plane; and the measuring sizes of particle images formed on said viewing screen.

Claim 16

In a method of evaluating particles as defined in claim 12, the steps that include: positioning a photosensitive screen at said image plane; reproducing the image formed at said screen as an optical image on a viewing screen thereby forming on said viewing screen an areal image of particles in said sample zone; and measuring the dimensions of the particle images formed on said viewing screen to determine the sizes of said particles.

Claim 17

In apparatus for evaluating liquid aerosol particles suspended in air having a light transmitter for transmitting radiation as a beam along an optical axis to a sample zone and having optical means having optical surfaces for transmitting radiation from an object plane in said sample zone along said optical axis and for focusing images of particles in said object zone at a picture plane, said optical means rendering said object plane conjugate with respect to said picture plane, whereby images of particles in said object plane are sharply defined in said picture plane; the improvement comprising: sample supply means for directing a stream of said particles into said sample zone along a path transverse to said optical axis; and means including wall members on opposite sides of said sample zone and having openings therein through which said optical axis passes for confining the flow of said stream to a narrow region at said object plane and for impeding the flow of aerosol particles toward said optical surface.

Claim 18

In apparatus for evaluating liquid aerosol particles suspended in air having a light transmitter for transmitting radiation as a beam along an optical axis to a sample zone and having optical means having optical surfaces for transmitting radiation from an object plane in said sample zone along said optical axis and for focusing images of particles in said object zone at a picture plane, said optical means rendering said object plane conjugate with respect to said picture plane, whereby images of particles in said object plane are sharply defined in said picture plane; the improvement comprising: sample supply means for directing a stream of said particles into said sample zone along a path transverse to said optical axis; and means including wall members on opposite sides of said sample zone and having openings therein through which said optical axis passes for confining the flow of said stream to a narrow region at said object plane and for impeding the flow of aerosol particles toward said optical surface.

Claim 19

In apparatus for evaluating particles, as defined in claim 15; means for recording signals representative of an areal image formed in said picture plane; a viewing screen; means for reproducing on said viewing screen said signals as a visible areal image of the particle images formed in said picture plane; and means on said viewing screen for measuring the sizes of the particles imaged thereon.

Claim 20

In apparatus for evaluating particles as defined in claim 15, in which said sample supply means comprises first and second convex members having small coaxial apertures that provide such openings on opposite sides of said sample zone, the wall of said first convex member diverging away from said optical axis on the upbeam side of said sample zone and the wall of said second convex member diverging away from said optical axis on the downbeam side of said sample zone.

Claim 21

In apparatus for evaluating particles as defined in claim 17, comprising means for supplying gas under pressure forcing air to flow gently through said apertures into said sample zone from opposite sides thereof while still permitting the aerosol particles to flow to said sample zone.

Claim 22

In a method of evaluating aerosol particles suspended in air, the steps that comprise: establishing an optical axis; establishing a sample zone at a position along said axis; establishing an image plane that is transverse to said optical axis; establishing in said sample zone an object plane that is transverse to said optical axis; optically conjugating said object plane with respect to said image plane by positioning optical elements between said planes whereby particles in said object plane are brought to a sharp focus in said image plane; transmitting a beam of radiation along said optical axis towards said sample zone; flowing air in which said aerosol particles are suspended to enter said sample zone along a path transverse to said optical axis; interposing on opposite sides of said sample zone two walls having openings therein with said optical axis passing through said openings, thereby restricting the flow of said air to a narrow region on both sides of said object plane thereby largely concentrating such aerosol particles to a region approximating the depth of focus at the object plane, whereby the images of such particles are focused on said image plane with little interference from out-of-focus images of particles outside said narrow region; whereby images of such aerosol particles in said object plane are sharply defined in said picture plane.

Claim 23

In a method of evaluating aerosol particles suspended in air, the steps that comprise: establishing an optical axis; establishing a sample zone at a position along said axis; establishing an image plane that is transverse to said optical axis; establishing in said sample zone an object plane that is transverse to said optical axis; optically conjugating said object plane with respect to said image plane by positioning optical elements between said planes whereby particles in said object plane are brought to a sharp focus in said image plane; transmitting a beam of radiation along said optical axis towards said sample zone; flowing air in which said aerosol particles are suspended to enter said sample zone along a path transverse to said optical axis; interposing on opposite sides of said sample zone two walls having openings therein with said optical axis passing through said openings, thereby restricting the flow of said air to a narrow region on both sides of said object plane thereby largely concentrating such aerosol particles to a region approximating the depth of focus at the object plane, whereby the images of such particles are focused on said image plane with little interference from out-of-focus images of particles outside said narrow region; whereby images of such aerosol particles in said object plane are sharply defined in said picture plane.

Claim 24

In a method for evaluating aerosol particles suspended in air as defined in claim 19, the additional step that comprises: flowing gas gently through said openings into said sample zone from both sides thereof while still permitting air in which said aerosol particles are suspended to enter said sampld zone along a path transverse to said optical axis.

Claim 25

In a method for evaluating particles as defined in claim 12, the additional step that comprises: forcing fluid gently through said openings into said sample zone from both sides thereof while still permitting said stream of particles to enter said sample zone along a path transverse to said optical axis.