US3845386A
Expired / Lapsed
US
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Method of and an apparatus for counting fibers
Assignee: IIT Research Institute
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Filing: 1973-07-02
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Granted: 1974-10-29
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Expires: 1993-07-02
Abstract
Abstract A method and apparatus are provided for distinguishing microscopic size, elongated fiber-like particles from cubically shaped, irregularly shaped, or spherically shaped particles in a mixture suspended in an electrically conducting liquid medium and for counting the fiber-like particles. In accordance with the method, an electrical zone sensing apparatus is provided with a screen means having microscopic openings therein of predetermined size to filter from the suspension particles having an effective area larger than the size of screen openings. Particles passing through the screen and through the sensing aperture of the zone sensing apparatus are separately sized by volume characteristics of electrical signals generated. The electrical signals having predetermined volume characteristics associated with the maximum spherical particles for passing through the screen openings are counted as non-fiber particles; whereas signals having larger volume characteristics are separately counted and designated as fibers. By the use of screens of successively smaller sizes, the larger particles including fibers having larger transverse cross sections may be successively filtered from the suspension and from reaching the sensing aperture. Therefore, smaller fibers having smaller cross-sectional area may be distinguished from particles having diameters approximating that of the smaller screen size openings.
Inventors
- 👤 R Davies
- 👤 R Karuhn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 00:08
CPC Classifications
G; G01; G01N; G01N15/00; G01N15/10; G01N15/1031; G01N15/12; G01N15/13; G01N15/134; G01N2015/0042; G01N2015/0053; G01N2015/0057
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
153 words
A method for electrically sensing and sizing small elongated fiber particles suspended in an electrolyte to form a suspension within a vessel comprising the steps of: passing the particles and electrolyte through a screen means having openings of a predetermined size therein, passing the particles having been screened through an electrical zoning sensing aperture along with the electrolyte, electrically sensing the particles passing through said aperture and generating electrical signals having a characteristic indicative of the volume of the particle passing through said aperture, classifying the signals according to the volume characteristics thereof, counting the classified signals having volume characteristics equal to or less than the predetermined volume associated with the maximum size of spherical particles capable of passing through said screen openings, and separately counting as fibers those classified signals having volume characteristics greater than said volume characteristics for said maximum size of spherical particles capable of passing through said screen means.
Claim 2
Independent Claim
153 words
A method for electrically sensing and sizing small elongated fiber particles suspended in an electrolyte to form a suspension within a vessel comprising the steps of: passing the particles and electrolyte through a screen means having openings of a predetermined size therein, passing the particles having been screened through an electrical zoning sensing aperture along with the electrolyte, electrically sensing the particles passing through said aperture and generating electrical signals having a characteristic indicative of the volume of the particle passing through said aperture, classifying the signals according to the volume characteristics thereof, counting the classified signals having volume characteristics equal to or less than the predetermined volume associated with the maximum size of spherical particles capable of passing through said screen openings, and separately counting as fibers those classified signals having volume characteristics greater than said volume characteristics for said maximum size of spherical particles capable of passing through said screen means.
Claim 3
Dependent Claim
79 words
A method in accordance with claim 1 including the steps of passing a portion of said suspension through a second screening means having openings of a second and predetermined size, eLectrically sensing said particles and generating and classifying said signals, said signals having characteristics equal to or less than a predetermined volume associated with a maximum spherical volume capable of flowing through said second screen openings being counted as non-fiber particles and larger volume signals being counted as fibers.
Claim 4
Dependent Claim
36 words
A method in accordance with claim 1 including the step of directing said liquid and fibers to flow along streamlined paths substantially parallel to the axis of the sensing aperture after passing through said screening means.
Claim 5
Dependent Claim
27 words
A method in accordance with claim 1 including the step of measuring the pulse height and pulse length and relating the pulse volume to a fiber size.
Claim 6
Dependent Claim
25 words
A method in accordance with claim 1 including the step of back flushing said screen to remove therefrom fibers in or about the screen means.
Claim 7
Dependent Claim
56 words
A method in accordance with claim 1 in which the step of providing screens having openings with a maximum dimension thereof being between 5 to 30 microns and calibrating said counting means to count fibers having an aspect ratio of two or less as non-fibers and particles having an aspect ratio greater than two as fibers.
Claim 8
Independent Claim
200 words
An apparatus for electrically sensing and sizing small elongated fiber particles suspended in an electrolyte to form a suspension, said apparatus comprising means for containing the suspension, receiving means for receiving the suspension subsequent to a sensing and sizing of the particles, means defining at least one aperture interconnecting in fluid communication said containing means and said receiving means and through which said particles pass to be sensed and sized in the course of travel from said containing means to said receiving means, means for electrically sensing the particles passing through said aperture and for generating an electrical signal having a characteristic indicative of the volume of the particle passing through said aperture, a plurality of filter means each sequentially adapted to flow therethrough and each having a predetermined and different sizes of openings therein through which said electrolyte and said particles may flow, means to separate said electrical signals indicative of different volumes into categories which are related to a predetermined particle volume for passing through each of said filter means, and means for counting as fibers said particles being filtered and sensed with signals associated with volumes larger than said predetermined particle volume for a given filter means.
Claim 9
Independent Claim
200 words
An apparatus for electrically sensing and sizing small elongated fiber particles suspended in an electrolyte to form a suspension, said apparatus comprising means for containing the suspension, receiving means for receiving the suspension subsequent to a sensing and sizing of the particles, means defining at least one aperture interconnecting in fluid communication said containing means and said receiving means and through which said particles pass to be sensed and sized in the course of travel from said containing means to said receiving means, means for electrically sensing the particles passing through said aperture and for generating an electrical signal having a characteristic indicative of the volume of the particle passing through said aperture, a plurality of filter means each sequentially adapted to flow therethrough and each having a predetermined and different sizes of openings therein through which said electrolyte and said particles may flow, means to separate said electrical signals indicative of different volumes into categories which are related to a predetermined particle volume for passing through each of said filter means, and means for counting as fibers said particles being filtered and sensed with signals associated with volumes larger than said predetermined particle volume for a given filter means.
Claim 10
Dependent Claim
38 words
An apparatus in accordance with claim 7 in which said filter means are micromesh screens, said screens having generally square shaped openings therein with sides of the openings measuring within the range of about 5 to 30 microns.
Claim 11
Dependent Claim
33 words
An apparatus in accordance with claim 8 in which each of said screens is selectively moved into an aperture filtering position and a preceding filter screen is selectively removed from the operative position.
Claim 12
Dependent Claim
25 words
An apparatus in accordance with claim 9 in which a carrier means is provided for carrying one of said filter screens into the operative position.
Claim 13
Dependent Claim
51 words
An apparatus in accordance with claim 7 in which a mounting means is provided for releasably holding a filter means in an operative position for filtering, each of said filter means being inserted and removed from said mounting means in a predetermined sequence to size fibers of different transverse cross sections.
Claim 14
Dependent Claim
49 words
An apparatus in accordance with claim 7 in which several containing means, receiving means, apertures, and filter means are connected to said electrical means and to said means to separate said signals and to said counting means for operation in sequence to size and count fibers of different volumes.
Claim 15
Independent Claim
242 words
A method for electrically sensing and sizing microscopic fiber particles suspended in an electrolyte within a vessel comprising the steps of passing the particles and electrolyte through a first screen means having openiNgs of a predetermined size therein, passing the particles having been screened through an electrical zone sensing aperture along with the electrolyte, electrically sensing the particles passing through said aperture and generating electrical pulses each having an amplitude indicative of a volume of the particle passing through the aperture, classifying the pulses by amplitude and counting the classified signals in separate channels of a pulse amplitude distribution analyzer, designating as fibers those particles counted in channels associated with volumes larger than the channel counting pulses for largest spheres capable of passing through said first screen means, analyzing a portion of the suspension with a second screen means having openings of a smaller size by passing the particles and electrolyte through an electrical zone sensing aperture along with the electrolyte to generate electrical pulses having amplitudes indicative of the volumes of the particles passing through the aperture and said second screen means, classifying these latter pulses by amplitude in channels with a pulse distribution analyzer, and counting as fibers with diameters between said sizes of said first and second screen openings, those said classified pulses in channels associated with particle volumes larger than the channel for counting the maximum size of spherical particles capable of passing through said second screen openings.
Claim 16
Independent Claim
242 words
A method for electrically sensing and sizing microscopic fiber particles suspended in an electrolyte within a vessel comprising the steps of passing the particles and electrolyte through a first screen means having openiNgs of a predetermined size therein, passing the particles having been screened through an electrical zone sensing aperture along with the electrolyte, electrically sensing the particles passing through said aperture and generating electrical pulses each having an amplitude indicative of a volume of the particle passing through the aperture, classifying the pulses by amplitude and counting the classified signals in separate channels of a pulse amplitude distribution analyzer, designating as fibers those particles counted in channels associated with volumes larger than the channel counting pulses for largest spheres capable of passing through said first screen means, analyzing a portion of the suspension with a second screen means having openings of a smaller size by passing the particles and electrolyte through an electrical zone sensing aperture along with the electrolyte to generate electrical pulses having amplitudes indicative of the volumes of the particles passing through the aperture and said second screen means, classifying these latter pulses by amplitude in channels with a pulse distribution analyzer, and counting as fibers with diameters between said sizes of said first and second screen openings, those said classified pulses in channels associated with particle volumes larger than the channel for counting the maximum size of spherical particles capable of passing through said second screen openings.
Claim 17
Dependent Claim
46 words
A method in accordance with claim 13 including the step of passing the particles through a third screen means having openings larger than the diameters of the spherical particles or the diameters of the fiber particles to obtain a total count of particles in said suspension.
Claim 18
Independent Claim
276 words
A method for analyzing a fiber distribution in an electrolyte suspension by ranges of diameters and lengths with an electrical zone sensing apparatus and a volume distribution analyzer counter means comprising the steps of: analyzing the suspension by passing the electrolyte and particles through a first screen means having openings of a first predetermined size with particles of sizes larger than said openings not passing through said first screen means, generating electrical pulses with said electrical zoning sensing means for each particle passing through said first screen means, each pulse being indicative of the particle volume passing through said zone sensing means, classifying the pulses by volumes with said volume distribution analyzer counter means and separately counting the pulses for each of said classified volumes, designating as fibers those pulses counted and classified as having volumes larger than the volume of the largest spherical particle capable of passing through said opening in said first screen means, analyzing the suspension a second time with a second screen means having openings of a size smaller than said openings of said first screen means by passing through said second screen means particles having diameters less than the size of said second screen openings and generating electrical pulses with said electrical zone sensing means indicative of a particle volume, classifying the pulses by volumes with said volume distribution analyzer means and separately counting the pulses for said classified volumes, and designating as fibers having diameters between the sizes of the first and second screen openings those pulses having classified volumes larger than the pulse volume for the maximum size of spherical particles capable of passing through said second screen openings.
Claim 19
Independent Claim
276 words
A method for analyzing a fiber distribution in an electrolyte suspension by ranges of diameters and lengths with an electrical zone sensing apparatus and a volume distribution analyzer counter means comprising the steps of: analyzing the suspension by passing the electrolyte and particles through a first screen means having openings of a first predetermined size with particles of sizes larger than said openings not passing through said first screen means, generating electrical pulses with said electrical zoning sensing means for each particle passing through said first screen means, each pulse being indicative of the particle volume passing through said zone sensing means, classifying the pulses by volumes with said volume distribution analyzer counter means and separately counting the pulses for each of said classified volumes, designating as fibers those pulses counted and classified as having volumes larger than the volume of the largest spherical particle capable of passing through said opening in said first screen means, analyzing the suspension a second time with a second screen means having openings of a size smaller than said openings of said first screen means by passing through said second screen means particles having diameters less than the size of said second screen openings and generating electrical pulses with said electrical zone sensing means indicative of a particle volume, classifying the pulses by volumes with said volume distribution analyzer means and separately counting the pulses for said classified volumes, and designating as fibers having diameters between the sizes of the first and second screen openings those pulses having classified volumes larger than the pulse volume for the maximum size of spherical particles capable of passing through said second screen openings.
Claim 20
Dependent Claim
113 words
A method in accordance with claim 13 including the further steps of: selecting a third screen means having openings less than the diameter of the smallest fiber particles thought to be in said suspension and passing the particles and electrolyte through said third screen means and electrical zone sensing aperture to generate electrical pulses indicative of the volume of particles passing through said third screen means, classifying the latter pulses according to volume characteristics, and deSignating as fibers having diameters between the sizes of said second screen means and said third screen means those classified volumes larger than the volumes of the maximum spherical particles capable of passing through said third screen means.
References Cited (Backward Citations)
US3515884A
Cited
US3739268A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-28 | 1978-04-29 | 1978-10-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-28 | 1982-04-29 | 1982-10-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-28 | 1986-04-29 | 1986-10-29 | $7700.00 | Window Closed / Lapsed |