US4781460A
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System for measuring the size distribution of particles dispersed in a fluid
Assignee: Coulter Electronics of New England Inc
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Filing: 1987-06-29
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Granted: 1988-11-01
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Expires: 2007-06-29
Abstract
Abstract An apparatus and method which provides a measure of the size distribution of particles dispersed in a fluid based upon an optimum combination of CLS measurements and DLS measurements. The measurement is characterized by relatively high resolution particle sizing. DLS data representative of the autocorrelation function, or power spectrum, of the detected intensity of scattered light for m measurement conditions of a sample, is optimally combined with CLS data representative of the average total detected intensity of scattered light for n measurement conditions, to provide an angle-independent, high resolution size distribution v(r), where m≧1, n≧0, m+n≧2, and at least two of the measurement conditions are different. The size distribution may be expressed in terms of the continuous function v(r) or the histogram v, and may represent distributions weighted by mass, volume, number, surface area, or other measures.
Inventors
- 👤 Steven E. Bott
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 11:30
CPC Classifications
G; G01; G01N; G01N15/00; G01N15/02; G01N15/0205; G01J; G01J3/00; G01J3/28; G01J3/44; G01J3/4412; G01N15/0211; G01N2015/0222
Claims Analysis
Total Claims: 46
Claim 1
Independent Claim
379 words
A system for measuring the size distribution v(r) of particles dispersed in a fluid sample, where r is representative of particle size, comprising: A. illumination means for illuminating said sample with a light beam directed along an input axis, B. detector means for detecting the intensity of light scattered from said light beam by said sample for m measurements made under an associated one of a set of m measurement conditions, and for n measurements made under an associated one of a set of n measurement conditions, where m is an integer equal to or greater than one, and n is an integer equal to or greater than zero, and the sum of m and n is equal to or greater than two, and at least two of said m+n measurement conditions are different, said detector means further including: i. means for generating m intensity signals, each of said intensity signals being representative of the detected intensity of said scattered light as a function of time under a corresponding one of the measurement conditions of said set of m measurement conditions, ii. means for generating n average signals, each of said n average signals being representative of the average intensity of said scattered light detected under a corresponding one of the measurement conditions of said set of n measurement conditions, C. autocorrelation means for generating m correlation signals, each of said correlation signals being representative of the autocorrelation function of a corresponding one of said intensity signals and being equal to an associated transformation of said distribution v(r), D. size processing means responsive to said correlation signals and said average signals, including: i. preprocessor means responsive to said m correlation signals for generating a composite correlation signal, ii. means for generating a composite scattered light signal from said composite correlation signal and said n average signals iii. means for determining a composite transformation operator J -1 related to said associated transformations and said n average signals, iv. means for transforming said composite scattered light signal in accordance with said determined composite transformation operator J -1 to generate a size distribution signal representative of said distribution v(r), and E. means for controlling said m+n measurement conditions whereby said intensity signals are mutually independent and said average signals are mutually independent.
Claim 2
Independent Claim
379 words
A system for measuring the size distribution v(r) of particles dispersed in a fluid sample, where r is representative of particle size, comprising: A. illumination means for illuminating said sample with a light beam directed along an input axis, B. detector means for detecting the intensity of light scattered from said light beam by said sample for m measurements made under an associated one of a set of m measurement conditions, and for n measurements made under an associated one of a set of n measurement conditions, where m is an integer equal to or greater than one, and n is an integer equal to or greater than zero, and the sum of m and n is equal to or greater than two, and at least two of said m+n measurement conditions are different, said detector means further including: i. means for generating m intensity signals, each of said intensity signals being representative of the detected intensity of said scattered light as a function of time under a corresponding one of the measurement conditions of said set of m measurement conditions, ii. means for generating n average signals, each of said n average signals being representative of the average intensity of said scattered light detected under a corresponding one of the measurement conditions of said set of n measurement conditions, C. autocorrelation means for generating m correlation signals, each of said correlation signals being representative of the autocorrelation function of a corresponding one of said intensity signals and being equal to an associated transformation of said distribution v(r), D. size processing means responsive to said correlation signals and said average signals, including: i. preprocessor means responsive to said m correlation signals for generating a composite correlation signal, ii. means for generating a composite scattered light signal from said composite correlation signal and said n average signals iii. means for determining a composite transformation operator J -1 related to said associated transformations and said n average signals, iv. means for transforming said composite scattered light signal in accordance with said determined composite transformation operator J -1 to generate a size distribution signal representative of said distribution v(r), and E. means for controlling said m+n measurement conditions whereby said intensity signals are mutually independent and said average signals are mutually independent.
Claim 3
Dependent Claim
86 words
A system according to claim 1 wherein said preprocessor means includes: i. means responsive to said m correlation signals for generating m moment signals, said m moment signals being representative of at least one of the moments of each of said m correlation signals other than the zero th moments of said m correlation signals, ii. means for generating a weighted direct sum signal, said weighted sum signal being representative of the direct sum of said m moment signals and corresponding to said composite correlation signal.
Claim 4
Dependent Claim
43 words
A system according to claim 2 wherein said means for generating said composite scattered light signal includes means for generating the direct sum of said composite correlation signal and said n average signals, said direct sum corresponding to said composite scattered light signal.
Claim 5
Dependent Claim
79 words
A system according to claim 1 wherein said preprocessor means includes: i. means responsive to said m correlation signals for generating m unity normalized correlation signals, each of said unity normalized correlation signals being representative of the unity normalized form of the corresponding one of said m correlation signals, ii. means for generating a direct sum signal, said sum signal being representative of the direct sum of said unity normalized correlation signals, and corresponding to said composite correlation signal.
Claim 6
Dependent Claim
43 words
A system according to claim 4 wherein said means for generating said composite scattered light signal includes means for generating the direct sum of said composite correlation signal and said n average signals, said direct sum corresponding to said composite scattered light signal.
Claim 7
Dependent Claim
39 words
A system according to claim 1 wherein said preprocessor includes: i. means for generating a direct sum signal, said sum signal being representative of the direct sum of said m correlation signals and corresponding to said composite correlation signal.
Claim 8
Dependent Claim
43 words
A system according to claim 6 wherein said means for generating said composite scattered light signal includes means for generating the direct sum of said composite correlation signal and said n average signals, said direct sum corresponding to said composite scattered light signal.
Claim 9
Dependent Claim
25 words
A system according to claim 1 wherein said illumination means includes means for directly illuminating said m points with a portion of said light beam.
Claim 10
Dependent Claim
26 words
A system according to claim 1 wherein said illumination means includes means for preventing any of said beam from directly illuminating any of said m points.
Claim 11
Dependent Claim
58 words
A system according to claim 1 wherein said autocorrelation means includes an autocorrelator means for generating said m correlation signals as time domain autocorrelation signals g i (t) where t is time and i=1, . . . , m, each of said m autocorrelation signals corresponding to the autocorrelation of a corresponding one of said m intensity signals.
Claim 12
Dependent Claim
62 words
A system according to claim 1 wherein said autocorrelation means includes a power spectrum means for generating said m correlation signal as frequency domain power spectrum signals G i (f) where f is frequency and i=1, . . . , m, each of said m power spectrum signals corresponding to the power spectrum of a corresponding one of said m intensity signals.
Claim 13
Dependent Claim
40 words
A system according to claim 1 wherein said associated transformations are linear transformations and wherein said composite transformation operator J -1 is the generalized inverse of the operator corresponding to the direct sum of the operators for said associated transformations.
Claim 14
Dependent Claim
32 words
A system according to claim 12 wherein said inverse transformation operator J -1 corresponds to the inverse of the matrix corresponding to the direct sum of the matrices of said associated transformations.
Claim 15
Dependent Claim
60 words
A system according to claim 12 wherein said inverse tranformation operator J -1 corresponds to [J t J+αH] -1 J t where J is the matrix corresponding to the direct sum of the matrices corresponding to said associated transformations, J t is the transpose of the matrix J, H is a conditioning matrix, and alpha (α) is a smoothing parameter.
Claim 16
Dependent Claim
82 words
A system according to claim 12 wherein said inverse transformation operator J -1 corresponds to [J t J+αH] -1 J t where J is the matrix corresponding the direct sum of the matrices corresponding to said associated tranformations, J t is the transpose of the matrix J, H is a conditioning matrix, and alpha (α) is a smoothing parameter and where all components of the vector representative of said distribution function v(r) are constrained to be greater than or equal to zero.
Claim 17
Dependent Claim
125 words
A system according to claim 1 wherein said associated transformations are non-linear and wherein said size distribution is characterized by v(r,p), where p is a characterization parameter vector having K components, and wherein said composite transformation operator J -1 is the p solution algorithm for ##EQU12## where i is an integer 1, . . . , m, j is an integer 1, . . . , q, l is an integer 1, . . . , k, p l is the l th component of p and where g i (t j ) is the autocorrelation function of the intensity signal for the i th of said angle at the j th time interval and J ij is an operator related to the associated transformations.
Claim 18
Dependent Claim
10 words
A system according to claim 1 wherein m≧1 and n≧1.
Claim 19
Dependent Claim
10 words
A system according to claim 1 wherein m≧2 and n≧0.
Claim 20
Dependent Claim
10 words
A system according to claim 2 wherein m≧1 and n≧1.
Claim 21
Dependent Claim
10 words
A system according to claim 2 wherein m≧2 and n=0.
Claim 22
Dependent Claim
10 words
A system according to claim 4 wherein m≧1 and n≧1.
Claim 23
Dependent Claim
10 words
A system according to claim 4 wherein m≧2 and n=0.
Claim 24
Dependent Claim
10 words
A system according to claim 6 wherein m≧1 and n≧1.
Claim 25
Dependent Claim
10 words
A system according to claim 6 wherein m≧2 and n=0.
Claim 26
Dependent Claim
88 words
A system according to claim 1 wherein said measurement condition controlling means comprises means for establishing the position of said detector means whereby one or more of said m intensity signals is representative of the intensity of light from said light beam at points angularly displaced from said input axis, and one or more of said n average signals is representative of the average intensity of said scattered light at points angularly displaced from said input axis different from said points for which said intensity signals are generated.
Claim 27
Dependent Claim
65 words
A system according to claim 1 wherein said measurement condition controlling means comprises means operative during at least one of said m+n measurements for selectively controlling the polarization of light from said beam incident on said sample to have a first predetermined polarization, and for selectively controlling the polarization of light scattered from said sample incident on said detector to have a said first polarization.
Claim 28
Dependent Claim
77 words
A system according to claim 1 wherein said measurement condition controlling means comprises means operative during at least one of said m+n measurements for selectively controlling the polarization of light from said beam incident on said sample to have a second predetermined polarization, and for selectively controlling the polarization of light scattered from said sample incident on said detector to have said second polarization, and wherein said second predetermined polarization is orthogonal to said first predetermined polarization.
Claim 29
Dependent Claim
13 words
A system according to claim 26 wherein said first predetermined polarization is circular.
Claim 30
Dependent Claim
15 words
A system according to claim 27 wherein said first and second predetermined polarizations are circular.
Claim 31
Dependent Claim
12 words
A system according to claim 26 wherein first predetermined polarization is linear.
Claim 32
Dependent Claim
14 words
A system according to claim 27 wherein first and second predetermined polarizations are linear.
Claim 33
Dependent Claim
64 words
A system according to claim 1 wherein said measurement condition controlling means comprises means operative during at least one of said m+n measurement for selectively controlling the temperature of said sample to m at a first predetermined temperature and operative during at least one other of said m+n measurements for selectively controlling the temperature of said sample to be at a second predetermined temperature.
Claim 34
Dependent Claim
32 words
A system according to claim 25 wherein said detector means includes a first sensor means for generating said m intensity signals and a second sensor means for generating said n average signals.
Claim 35
Dependent Claim
97 words
A system according to claim 33 wherein said second sensor means includes a first curvilinear array of spaced apart photosensors and a second curvilinear array of spaced apart photosensors, said first array extending along an arc disposed about said sample, wherein the photosensors in said first array are offset from said sample by relatively small angles measured from said input axis, and said second array extending along an arc disposed about said sample wherein the photosensors in said second array are offset from said sample by ninety degrees plus relatively small angles measured from said input axis.
Claim 36
Dependent Claim
16 words
A system according to claim 34 wherein said first and second arrays lie in orthogonal planes.
Claim 37
Dependent Claim
65 words
A system according to claim 34 including means for supporting a container for said sample, said container having opposed parallel planar lateral surfaces, said container having a rectangular cross-section bounded by said lateral surfaces, and wherein said supporting means includes means for maintaining one pair of lateral surfaces perpendicular to said input axis, and the other pair of lateral surfaces parallel to said input axis.
Claim 38
Dependent Claim
65 words
A system according to claim 35 including means for supporting a container for said sample, said container having opposed parallel planar lateral surfaces, said container having a rectangular cross-section bounded by said lateral surfaces, and wherein said supporting means includes means for maintaining one pair of lateral surfaces perpendicular to said input axis, and the other pair of lateral surfaces parallel to said input axis.
Claim 39
Independent Claim
358 words
A method for measuring the size distribution v(r) of particles dispersed in a fluid sample, where r is representative of particle size, comprising the steps of: A. illuminating said sample with a light beam directed along an input axis, B. detecting the intensity of light scattered from said light beam by said sample for m measurements made under an associated one of a set of m measurement conditions, and for n measurements made under an associated one of a set of n measurement conditions, where m is an integer equal to or greater than one, and n is an integer equal to or greater than zero, and the sum of m and n is equal to or greater than two, and at least two of said m+n measurement conditions are different, including the substeps of: i. generating m intensity signals, each of said intensity signals being representative of the detected intensity of said scattered light as a function of time under a corresponding one of the measurement conditions of said set of m measurement conditions, ii. generating n average signals, each of said n average signals being representative of the average intensity of said scattered light detected under a corresponding one of the measurement conditions of said set of n measurement conditions, C. generating m correlation signals, each of said correlation signals being representative of the autocorrelation function of a corresponding one of said intensity signals and being equal to an associated transformation of said distribution v(r), D. in response to said correlation signals and said average signals, including the substeps of: i. preprocessing said m correlation signals for generating a composite correlation signal, ii. generating a composite scattered light signal from said composite correlation signal and said n average signals iii. determining a composite transformation operator J -1 related to said associated transformations and said n average signals, iv. transforming said composite scattered light signal in accordance with said determined composite transformation operator J -1 to generate a size distribution signal representative of said distribution v(r), and E. controlling said m+n measurement conditions whereby said intensity signals are mutually independent and said average signals are mutually independent.
Claim 40
Independent Claim
358 words
A method for measuring the size distribution v(r) of particles dispersed in a fluid sample, where r is representative of particle size, comprising the steps of: A. illuminating said sample with a light beam directed along an input axis, B. detecting the intensity of light scattered from said light beam by said sample for m measurements made under an associated one of a set of m measurement conditions, and for n measurements made under an associated one of a set of n measurement conditions, where m is an integer equal to or greater than one, and n is an integer equal to or greater than zero, and the sum of m and n is equal to or greater than two, and at least two of said m+n measurement conditions are different, including the substeps of: i. generating m intensity signals, each of said intensity signals being representative of the detected intensity of said scattered light as a function of time under a corresponding one of the measurement conditions of said set of m measurement conditions, ii. generating n average signals, each of said n average signals being representative of the average intensity of said scattered light detected under a corresponding one of the measurement conditions of said set of n measurement conditions, C. generating m correlation signals, each of said correlation signals being representative of the autocorrelation function of a corresponding one of said intensity signals and being equal to an associated transformation of said distribution v(r), D. in response to said correlation signals and said average signals, including the substeps of: i. preprocessing said m correlation signals for generating a composite correlation signal, ii. generating a composite scattered light signal from said composite correlation signal and said n average signals iii. determining a composite transformation operator J -1 related to said associated transformations and said n average signals, iv. transforming said composite scattered light signal in accordance with said determined composite transformation operator J -1 to generate a size distribution signal representative of said distribution v(r), and E. controlling said m+n measurement conditions whereby said intensity signals are mutually independent and said average signals are mutually independent.
Claim 41
Dependent Claim
86 words
A method according to claim 38 wherein said preprocessng step includes the substeps of: i. in response to said m correlation signals, generating m moment signals, said m moment signals being representative of at least one of the moments of each of said m correlation signals other than the zero th moments of said m correlation signals, ii. generating a weighted direct sum signal, said weighted sum signal being representative of the direct sum of said m moment signals and corresponding to said composite correlation signal.
Claim 42
Dependent Claim
44 words
A method according to claim 39 wherein said step of generating said composite scattered light signal includes the step of generating the direct sum of said composite correlation signal and said n average signals, said direct sum corresponding to said composite scattered light signal.
Claim 43
Dependent Claim
79 words
A method according to claim 38 wherein said preprocessing steps includes the substeps of: i. in response to said m correlation signals, generating m unity normalized correlation signals, each of said unity normalized correlation signals being representative of the unity normalized form of the corresponding one of said m correlation signals, ii. generating a direct sum signal, said sum signal being representative of the direct sum of said unity normalized correlation signals, and corresponding to said composite correlation signal.
Claim 44
Dependent Claim
44 words
A method according to claim 41 wherein said step of generating said composite scattered light signal includes the step of generating the direct sum of said composite correlation signal and said n average signals, said direct sum corresponding to said composite scattered light signal.
Claim 45
Dependent Claim
41 words
A method according to claim 38 wherein said preprocessing step includes the step of: i. generating a direct sum signal, said sum signal being representative of the direct sum of said m correlation signals and corresponding to said composite correlation signal.
Claim 46
Dependent Claim
44 words
A method according to claim 43 wherein said step of generating said composite scattered light signal includes the step of generating the direct sum of said composite correlation signal and said n average signals, said direct sum corresponding to said composite scattered light signal.
References Cited (Backward Citations)
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