System for making particle measurements

Claim 1

A system for particle measurement employing radiation scattering wherein there is relative movement of a particlecontaining medium and particles contained therein with reference to the measurement system comprising radiation source means emitting radiation in beam form, photodetector means having a radiation acceptance geometry whose projection intercepts said beam of said source means, a scattering volume disposed between said source means and said photodetector means and defined by the interception of said beam by said projected acceptance geometry of said photodetector means, said scattering volume being disposed within a medium containing the particle to be measured, means for effecting relative movement between the particles to be measured and the scattering volume without applying forces to the particle-containing medium which effect substantial change in the particle-containing medium that alters the condition or ditribution of the particles in the medium, and means pulsing said light source means at a rate that results in illumination of said scattering volume not more than once during each time period equal to the time period required for a particle to traverse said scattering volume in a direction generally parallel to the direction of movement of said particle-containing medium under the then existing conditions of particle movement through said scattering volume and at least once during the interval between the exit of an illuminated particle from said scattering volume and the entry of a further illuminated particle into said scattering volume, whereby the particle to be measured moves substantially undisturbed through said scattering volume and while disposed within said scattering volume is impinged by said beam and scatters a portion of said beam toward the photodetector means to cause said photodetector means to develop an electrical signal that is proportional to the intensity of the radiation scattered to said photodetector means by said particle and each such output electrical signal that is representative of a particle of interest within said scattering volume is separated from each other such signal representative of a particle of interest by an output electrical signal that is not representative of a particle of interest.

Claim 2

A system for particle measurement employing radiation scattering wherein there is relative movement of a particlecontaining medium and particles contained therein with reference to the measurement system comprising radiation source means emitting radiation in beam form, photodetector means having a radiation acceptance geometry whose projection intercepts said beam of said source means, a scattering volume disposed between said source means and said photodetector means and defined by the interception of said beam by said projected acceptance geometry of said photodetector means, said scattering volume being disposed within a medium containing the particle to be measured, means for effecting relative movement between the particles to be measured and the scattering volume without applying forces to the particle-containing medium which effect substantial change in the particle-containing medium that alters the condition or ditribution of the particles in the medium, and means pulsing said light source means at a rate that results in illumination of said scattering volume not more than once during each time period equal to the time period required for a particle to traverse said scattering volume in a direction generally parallel to the direction of movement of said particle-containing medium under the then existing conditions of particle movement through said scattering volume and at least once during the interval between the exit of an illuminated particle from said scattering volume and the entry of a further illuminated particle into said scattering volume, whereby the particle to be measured moves substantially undisturbed through said scattering volume and while disposed within said scattering volume is impinged by said beam and scatters a portion of said beam toward the photodetector means to cause said photodetector means to develop an electrical signal that is proportional to the intensity of the radiation scattered to said photodetector means by said particle and each such output electrical signal that is representative of a particle of interest within said scattering volume is separated from each other such signal representative of a particle of interest by an output electrical signal that is not representative of a particle of interest.

Claim 7

A method for making in situ measurements of particles moving along a path comprising the steps of projecting a beam of radiation into a particle-containing medium, positioning a photodetector means at a location distant from said radiation beam, aligning said photodetector means with respect to said beam whereby the projected acceptance geometry of said photodetector means intercepts said beam at a location within the particle-containing medium to define a scattering volume, effecting relative movement between the particle to be measured and the scattering volume without applying forces to the particle-containing medium which effect substantial change in the particle-containing medium that alters the condition or distribution of the particles in the medium, admitting said beam of radiation to said scattering volume in pulses timed to illuminate said scattering volume not more than once each time period equal to the time period required for a particle to traverse said scattering volume in a direction generally parallel to the direction of movement of said particle-containing medium under the then existing conditions of particle movement through said scattering volume and at least once during the interval between the exit of an illuminated particle from said scattering volume and the entry of a further illuminated particle into said scattering volume, whereby the particle to be measured moves substantially undisturbed through said scattering volume and while disposed within said scattering volume is impinged by said beam and scatters a portion of said beam toward said photodetector means to cause said photodetector means to develop an electrical signal that is proportional to the intensity of the radiation scattered to said photodetector means by said particle and each such output electrical signal that is representative of a particle of interest within said scattering volume is separated from each other such signal representative of a particle of interest by an output electrical signal that is not representative of a particle of interest.

Claim 8

A method for making in situ measurements of particles moving along a path comprising the steps of projecting a beam of radiation into a particle-containing medium, positioning a photodetector means at a location distant from said radiation beam, aligning said photodetector means with respect to said beam whereby the projected acceptance geometry of said photodetector means intercepts said beam at a location within the particle-containing medium to define a scattering volume, effecting relative movement between the particle to be measured and the scattering volume without applying forces to the particle-containing medium which effect substantial change in the particle-containing medium that alters the condition or distribution of the particles in the medium, admitting said beam of radiation to said scattering volume in pulses timed to illuminate said scattering volume not more than once each time period equal to the time period required for a particle to traverse said scattering volume in a direction generally parallel to the direction of movement of said particle-containing medium under the then existing conditions of particle movement through said scattering volume and at least once during the interval between the exit of an illuminated particle from said scattering volume and the entry of a further illuminated particle into said scattering volume, whereby the particle to be measured moves substantially undisturbed through said scattering volume and while disposed within said scattering volume is impinged by said beam and scatters a portion of said beam toward said photodetector means to cause said photodetector means to develop an electrical signal that is proportional to the intensity of the radiation scattered to said photodetector means by said particle and each such output electrical signal that is representative of a particle of interest within said scattering volume is separated from each other such signal representative of a particle of interest by an output electrical signal that is not representative of a particle of interest.

Claim 9

A system for measuring relatively large particles employing radiation scattering wherein there is relative movement of a particle-containing medium with reference to the measurement system and said medium contains large and small particles comprising a radiation source means emitting a radiation beam directed into said particle-containing medium, a pair of photodetector means each having a radiation acceptance geometry whose projection intercepts said beam at spaced apart locations within said particle-containing medium, a plurality of scattering volumes disposed between said source means and respective ones of said photodetector means and defined by the interception of said beam by the respective projected acceptance geometries of said plurality of photodetector means, means for effecting relative movement between said particle-containing medium and said scattering volumes without applying forces to the particle-containing medium which effect substantial change in the particle-containing medium that alters the condition or distribution of the particles in the medium, whereby the particles in said medium move substantially undisturbed through said scattering volumes and while disposed within said scattering volumes are impinged by said beam and scatter a portion of said beam toward respective ones of said photodetector means to cause said plurality of photodetector means to develop respective electrical signals that are proportional to the intensity of the radiation scattered to each such photodetector means by said particles, said signals being developed substantially simultaneously by said photodetectors so that the mathematical probability of a large particle appearing in one of said scattering volumes at the time of measurement is substantially less than the mathematical probability of a large particle appearing simultaneously in the other of the scattering volumes and the signal developed by that photodetector whose scattering volume contains a large particle is greater than the signal developed by the other photodetectors, and means electrically subtracting the smaller of said signals from the larger signal.

Claim 10

A system for measuring relatively large particles employing radiation scattering wherein there is relative movement of a particle-containing medium with reference to the measurement system and said medium contains large and small particles comprising a radiation source means emitting a radiation beam directed into said particle-containing medium, a pair of photodetector means each having a radiation acceptance geometry whose projection intercepts said beam at spaced apart locations within said particle-containing medium, a plurality of scattering volumes disposed between said source means and respective ones of said photodetector means and defined by the interception of said beam by the respective projected acceptance geometries of said plurality of photodetector means, means for effecting relative movement between said particle-containing medium and said scattering volumes without applying forces to the particle-containing medium which effect substantial change in the particle-containing medium that alters the condition or distribution of the particles in the medium, whereby the particles in said medium move substantially undisturbed through said scattering volumes and while disposed within said scattering volumes are impinged by said beam and scatter a portion of said beam toward respective ones of said photodetector means to cause said plurality of photodetector means to develop respective electrical signals that are proportional to the intensity of the radiation scattered to each such photodetector means by said particles, said signals being developed substantially simultaneously by said photodetectors so that the mathematical probability of a large particle appearing in one of said scattering volumes at the time of measurement is substantially less than the mathematical probability of a large particle appearing simultaneously in the other of the scattering volumes and the signal developed by that photodetector whose scattering volume contains a large particle is greater than the signal developed by the other photodetectors, and means electrically subtracting the smaller of said signals from the larger signal.