Fine particle measuring method and system and a flow cell for use in the system

A fine particle measuring method in which laser beam having an intensity gradually increasing over at least the peripheral portion thereof and a portion inner of and near to the peripheral portion inward from the peripheral portion is radiated to fine particles in a sample fluid flowing speed in a direction to intersect a flow direction of said sample fluid, and scattered lights dispersed on the fine particles in a light scattering region are detected comprising:

• a first step of forming said laser beam into at least two parallel beams having respective intensity distributions, deviating from each other in a direction orthogonal both to said flow direction of said sample fluid and a direction of said laser beam in a range in which the beam spots of said laser beams overlap each other in said flow direction of said sample fluid, and deviating from each other by a given distance in said flow direction;
• a second step of detecting scattered lights dispersed on said fine particles passing said at least two parallel beams;
• a third step of measuring a time interval between at least two successive detected outputs of the scattered lights detected by the second step;
• a fourth step of extracting a pair of detected outputs of one and the same one of said fine particles, based on the time interval measured by the third step;
• a fifth step of selecting an area of said light scattering region to be detected, based on a value of said at least two detected outputs of the pair extracted by the fourth step;
• and
• a sixth step of measuring particle diameters of said fine particles, based on the value of said at least two detected outputs in said light scattering region in the area selected by the fifth step.

A fine particle measuring system comprising:

• at least one laser beam source;
• a first optical system for forming a laser beam from said laser beam source into at least two parallel beams which have respective given intensity distributions, which deviate from each other in a direction orthogonal both to a flow direction of a sample fluid and a direction of said laser beam in a range in which the beam spots of said laser beams overlap each other in said flow direction of said sample fluid, and which deviate from each other by a given distance in said flow direction;
• a flow passage for the sample fluid containing fine particles to flow through in a given direction, arranged so that said fine particles intersect said at least two parallel laser beams;
• a second optical system for forming scattered lights formed by said fine particles passing said at least two parallel laser beams into images at a given image point;
• light detecting means for detecting the scattered lights formed into the images by the second optical system to generate detected outputs;
• and
• measuring means for extracting scattered lights from one and the same one of said fine particle, based on a time interval between at least two detected outputs successively generated, selecting an area of a light scattering region to be detected, based on the ratio between values of said at least two detected outputs, and measuring particle diameters of said fine particles, based on the value of said at least two detected outputs thus extracted and selected.

A fine particle measuring method in which a laser beam having an intensity gradually increasing over at least peripheral portion thereof and a portion near to and inner of the peripheral portion inward from the peripheral portion is radiated to fine particles in a sample fluid flowing in a given direction and a given flow speed in a direction intersecting a flow direction of said sample fluid, and scattered lights form said fine particles in a light scattering region are detected comprising:

• a first step of forming said laser beam into two parallel linear polarized beams having respective given intensity distributions, deviating from each other in a direction substantially orthogonal both to said flow direction and a direction of the laser beam in a range in which the beam spots of said laser beams overlap each other, and having the polarization planes thereof orthogonal to each other;
• a second step of detecting two scattered lights formed simultaneously by said fine particles passing said two linear polarized beams;
• a third step of selecting an area of said light scattering region, based on a value of two detected outputs given by the second step;
• and
• a fourth step of correcting the value of said two detected outputs by preset procedure in the area selected by the third step, and, based on a result of the correction, measuring particle diameters of said fine particles.

The fine particle measuring method in which laser beam having an intensity gradually increasing over at least peripheral portion thereof and a portion near to and inner of the peripheral portion inward from the peripheral portion is radiated to fine particles in a sample fluid flowing in a given direction in a direction to intersect a flow direction of said sample fluid, and scattered lights form said fine particles in a light scattering region are detected comprising:

• a first step of forming said laser beam into a first and a second linear polarized beams, being parallel each other, having respective given intensity distributions, deviating from each other in a direction substantially orthogonal both to said flow direction and said direction of said laser beam in a range in which the beam spots of said laser beams overlap each other, and which have polarization planes substantially orthogonal to each other, and into a third parallel beam which deviates from said first and a second linear polarized beams by a given distance in said flow direction in a range in which the beam spots of said first and the second linear polarized beams overlap each other
• a second step of detecting a first to a third scattered lights formed by said fine particles passing said first and second linear polarized beams, and said third parallel beam
• a third step of measuring a time interval between a detected output of at least one of said first and said second scattered lights, and a detected output of said third scattered light;
• a fourth step of extracting a pair of detected outputs of one and the same one of said fine particles, based on a time interval measured by the third step;
• a fifth step of selecting an area of said light scattering region to be detected, based on a value of the pair of detected outputs of said first and second scattered lights detected substantially simultaneously by the second step;
• a sixth step of measuring particle diameters of said fine particles, based on the value of said detected outputs of said first and second scattered lights in the area of said light scattering region selected by the fifth step;
• a seventh step of computing a volume of said sample fluid passing the area of said light scattering region selected by the fifth step, based on the time interval measured by the third step;
• and
• an eighth step of computing particle diameter distributions, based on the particle diameters measured by the sixth step, and the volume of said sample fluid computed by the seventh step.

A fine particle measuring system comprising:

• at least one laser beam source;
• a first optical system for forming the laser beam from said laser beam source into parallel two linear polarized beams having respective given intensity distributions, deviating from each other in a direction orthogonal both to a flow direction of a sample fluid and a direction of said laser beam, and having their polarization planes orthogonal to each other;
• a flow passage for a sample fluid containing fine particles to flow in a given direction arranged to intersect said two linear polarized beams;
• a second optical system for forming scattered lights of said two polarized beams into images on a given image point;
• polarizing and dividing means for dividing the scattered lights formed in the images by the second optical system according to the polarization planes;
• light detecting means for detecting two respective divided scattered lights and generating detected outputs and;
• PG,164
• measuring means for selecting an area of a light scattering region to be detected, based on a value of said two detected outputs detected substantially simultaneously, and measuring particle diameters of said fine particles, based on the value of said selected two detected outputs in said selected area.

A fine particle measuring system comprising:

• at least one laser beam source;
• a first optical system for forming the laser beam into a first and a second linear polarized beams, being parallel each other, having respective given intensity distributions, deviating from each other in a direction orthogonal both to a flow direction of a sample fluid and a direction of the laser beam in a range in which the beam spots of said first and second linear polarized beams overlap each other, and having their polarization planes substantially orthogonal to each other, and into a third parallel beam deviating from said first and second linear polarized beams by a given distance in said flow direction;
• a flow passage for a sample fluid containing fine particles to flow through, arranged to intersect said first and second linear polarized beams, and said third parallel beam;
• a second optical system for forming scattered lights of said first and second linear polarized beams, and said third parallel beam against said fine particles into images on a given image point;
• polarizing and dividing means for dividing the scattered lights formed in the images by the second optical system according to the polarization planes;
• light detecting means for detecting the scattered lights divided according to the polarization planes and generating detected outputs;
• extracting means for extracting a pair of detected outputs of one and the same one of said fine particles, based on a peak of the occurrences of a time interval between two successively detected outputs;
• measuring means for selecting an area of a light scattering region to be detected, based on a value of at least two of said extracted pair of detected outputs generated by one and the same one of said fine particles passing said first and second linear polarized beams, and said third parallel beam, measuring particle diameters of said fine particles, based on the selected value of said two outputs, computing a volume of said sample fluid passing said selected area of the light scattering region, based on a time interval between at least one of the detected outputs of said first and second scattered lights, and the detected output of the third scattered light, an computing particle diameter distributions of said fine particles, based on said particle diameters and said volume of said sample fluid.

A fine particle measuring method in which laser beam having an intensity gradually increasing over at least the peripheral portion thereof and a portion inner of and near to the peripheral portion from the peripheral portion is radiated to fine particles contained in a sample fluid flowing in a given direction and at a given flow speed, and scattered lights against said fine particles in a light scattering region are detected comprising:

• a first step causing said laser beam to scan at a given speed and in a given direction so that said laser beam intersect said flow direction of said sample fluid orthogonally to a direction of said laser beam;
• a second step of restricting a radiation area of said laser beam to fine particles in said sample fluid by scanning direction of said laser beam;
• a third step of detecting scattered lights formed by said fine particles passing said laser beam;
• a fourth step of measuring particle diameters of said fine particles, based on the detected outputs given by the third step and
• a fifth step of measuring particle diameter distributions of said fine particles, based on a relative flow velocity of said sample fluid given as a vector sum of a scanning velocity of said laser beam and a flow velocity of said sample fluid.

A fine particle measuring method in which a laser beam having an intensity gradually increasing over at least the peripheral portion thereof and a portion inner of and near to the peripheral portion inward from the peripheral portion is radiated to fine particles in a sample medium, and scattered lights against said fine particles in a light scattering region are detected comprising:

• a first step of forming the laser beam into at least two parallel beams having respective intensity distributions;
• a second step of causing said at least two parallel beams to scan at a given speed and in a given direction so that said at least two parallel beams may pass said fine particles;
• a third step of detecting at least two scattered lights formed by one and the same one of said fine particles passing said at least two parallel beams among scattered lights formed by said fine particles passing said at least two parallel beams;
• a fourth step selecting an area of said light scattering region to be detected, based on a ratio between the values of at least two detected outputs generated by the third step;
• and
• a fifth step of measuring particle diameters of said fine particles, based on the value of said at least two detected outputs in said area selected by the fourth step.

A fine particle measuring method in which a laser beam having an intensity gradually increasing over at least the peripheral portion and a portion inner of and near to the peripheral portion inward from the peripheral portion is radiated to fine particles contained in a sample medium, and scattered lights against said fine particles in a light scattering region are detected comprising:

• a first step of forming the laser beam into at least two parallel beams having respective intensity distributions and deviating from each other by a given distance in a direction orthogonal to a direction of said laser beam;
• a second step of causing said at least two parallel beams to that when said sample medium is a sample fluid flowing in a given direction, the beam spots of said at least two parallel beams at least partially overlap each other in a relative flow direction given by a vector sum of a flow direction of said sample fluid and a scanning direction of said laser beam, and when said sample medium does not flow, the beam spots of said at least two parallel beams at least partially overlay each other in a relative flow direction given by a scanning direction of said laser beam;
• a third step of detecting scattered lights formed by said fine particles passing said at least two parallel beams;
• a fourth step of measuring a time interval between at least two successively generated detected outputs of the scattered lights detected by the third step;
• a fifth step of extracting a pair of detected outputs of one and the same of said fine particles, based on a time interval measured by the fourth step;
• a six step of selecting an area of said light scattering region to be detected, based on a ratio between the values of at least two detected outputs of said pair extracted by the fifth step;
• and
• a seventh step of measuring particle diameters of said fine particles, based on the value of said at least two detected outputs of said light scattering region in an area selected by the sixth step.

A fine particle measuring system comprising:

• a laser beam source;
• a first optical system for forming the laser beam from said laser beam source into a laser beam having an intensity gradually increasing over the peripheral portion thereof and a portion inner of and near to the peripheral portion inward from the peripheral portion;
• a flow passage for a sample fluid containing fine particles to be measured to flow in a given direction and at a given flow velocity, arranged to intersect said laser beam;
• scanning means for causing said laser beam to scan at a given speed and in a given direction so that said laser beam intersects a flow direction of said sample fluid orthogonally to a direction of said laser beam;
• radiating area restricting means for restricting the radiating area of said laser beam to fine particles in said sample fluid by a scanning direction of said laser beam;
• light detecting means for detecting scattered lights formed by said fine particles passing said laser beam;
• and
• fine particle measuring means for measuring particle diameters of said fine particles, based on a value of the detected outputs given by said light detecting means, and computing particle diameter distributions of said fine particles, based on a relative flow velocity of said sample fluid given as a vector sum of a scanning velocity of said laser beam and a flow velocity of said sample fluid, and a measuring result of particle diameters of said fine particles.

A fine particle measuring system comprising:

• at least one laser beam source;
• a first optical system for forming the laser beam from said laser beam source into at least two parallel beams having respective given intensity distributions, and deviating from each other by a given distance in a direction orthogonal to a direction of said laser beam;
• a sample reserving member for containing a sample medium containing fine particles to be measured in its flowing condition or stationary condition, arranged to intersect said at least two parallel beams;
• scanning means for causing said at least two parallel beams to that when said sample medium is a sample fluid flowing in a given direction, the beam spots of said at least parallel beams at least partially overlap each other in a relative flow direction given by a vector sum of a flow direction of said sample fluid and a scanning direction of said laser beam, and when said sample medium does not flow, the beam spots of said at least two parellel beams at least partially overlap each other in a relative flow direction given by a scanning direction of said laser beam;
• a second optical system for forming scattered lights of said at least two parallel beams against said fine particles into images at a given image point;
• light detecting means for detecting the scattered lights formed in the images by the second step and generating detected outputs;
• and
• measuring means for extracting scattered lights against one and the same one of said fine particles, based on a time interval between at least two of said detected outputs successively generated, selecting an area of light scattering region to be detected based on the values of said at least two detected output, and measuring particle diameters of said fine particles, based on the values of said at least two detected outputs thus extracted and selected.

A flow cell for use in a fine particle measuring system in which a measuring laser beam is radiated to a fluid to form scattered lights, and the scattered lights are observed to measure fine particles in said fluid, and which is so arranged that said fluid passing through a flow passage in the flow cell may pass said measuring beam comprising:

• a tubular member having a flow passage therein for said fluid to pass through and having a flat region over a given area, which is transparent to said measuring beam, provided at least on the outside surface thereof on the side of observation of scattered lights of said measuring beam;
• an incident block secured to said tubular member at a position of incidence of said measuring beam, and having the surface thereof except for a plane of incidence of said measuring beam opposite to said plane of incidence made sufficiently light absorptive;
• and
• said incident block is secured to said tubular member through a refractive index adjusting liquid.

A flow cell for use in a fine particle measuring system in which a measuring laser beam is radiated to a fluid to form scattered lights, and the scattered lights are observed to measure fine particles in said fluid, and which is so arranged that said fluid passing through a flow passage in the flow cell may pass said measuring beam comprising:

• a tubular member having a flow passage therein for said fluid to pass through and having a flat region over a given area, which is transparent to said measuring beam, provided at least on the outside surface thereof on the side of observation of scattered lights of said measuring beam;
• an incident block secured to said tubular member at a position of incidence of said measuring beam, and having the surface thereof except for a plane of incidence of said measuring beam and a transmission area for said measuring beam opposite to said plane of incidence made sufficiently light absorptive;
• and
• said incident block is elongated in a scanning direction of said measuring beam.

A flow cell for use in a fine particle measuring system in which measuring laser beam is radiated to a fluid to obtain scattered lights, and the scattered lights are observed to measure fine particles in said fluid, and which is so arranged that said fluid passing through a flow passage in the flow cell may pass said measuring beam comprising;

• a tubular member having a flow passage therein for said fluid to pass through and having a flat region over a given area, which is transparent to said measuring beam provided at least on the outside surface thereof on the side of observation of scattered lights of said measuring beam;
• an incident block secured to said tubular member at a position of incidence of said measuring beam, and having the surface thereof except for a plane of incidence of said measuring beam and a transmission area for said measuring beam opposite to said plane of incidence made sufficiently light absorptive;
• and
• a beam trap member secured to said tubular member at a position where said measuring beam passing said tubular member exits the same, and having a light receiving area for receiving the part of said measuring beam passing said tubular member made sufficiently light absorptive.