US5059909A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Determination of particle size and electrical charge
Assignee: Agilent Technologies Inc
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Filing: 1987-09-30
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Granted: 1991-10-22
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Expires: 2007-09-30
Abstract
Abstract A method for the determination of particle size and electric charge or zeta potential of particles dispersed in a fluid medium. The particle size and charge are determined from measurements of (1) the phase lag between an applied alternating electric field and the resulting particle velocity, and (2) the amplitude of the particle velocity. Also disclosed is the measurement of the interaction of sound waves and electric fields in the fluid medium over a range of frequencies to obtain the particle size and zeta potential.
Inventors
- 👤 Richard W. O'Brien
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 16:52
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/416; G01N27/447; G01N15/00; G01N15/02
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
136 words
A method for determining the particle charge and size distribution of particles in suspensions of arbitrary concentration in a fluid medium, comprising: applying at least one of an unsteady electric field of at least two different frequencies and an unsteady mechanical force of at least two different frequencies to the suspension to accelerate the particles; measuring a resulting acoustic wave generated by the particles as a result of the application at each frequency of unsteady electric field, or a resulting electrical response generated by the particles as a result of the application at each frequency of unsteady mechanical force; determining the frequency dependent electrophoretic mobility of the particles from the measured acoustic wave or electrical response at each of the applied frequencies; and calculating the particle size and charge distribution from the frequency dependent electrophoretic mobility.
Claim 2
Independent Claim
136 words
A method for determining the particle charge and size distribution of particles in suspensions of arbitrary concentration in a fluid medium, comprising: applying at least one of an unsteady electric field of at least two different frequencies and an unsteady mechanical force of at least two different frequencies to the suspension to accelerate the particles; measuring a resulting acoustic wave generated by the particles as a result of the application at each frequency of unsteady electric field, or a resulting electrical response generated by the particles as a result of the application at each frequency of unsteady mechanical force; determining the frequency dependent electrophoretic mobility of the particles from the measured acoustic wave or electrical response at each of the applied frequencies; and calculating the particle size and charge distribution from the frequency dependent electrophoretic mobility.
Claim 3
Dependent Claim
19 words
The method of claim 1 including the step of selecting the appropriate frequencies from an expected particle size range.
Claim 4
Dependent Claim
28 words
The method of claim 1, wherein the frequency dependent electrophoretic mobility is determined by applying an unsteady electric field to the suspension and measuring the resulting acoustic wave.
Claim 5
Dependent Claim
25 words
The method of claim 1, wherein the frequency dependent electrophoretic mobility is determined by applying an unsteady mechanical force and measuring the resulting electrical current.
Claim 6
Dependent Claim
25 words
The method of claim 1, wherein the frequency dependent electrophoretic mobility is determined by applying an unsteady mechanical force and measuring the resulting electrical voltage.
Claim 7
Dependent Claim
48 words
The method of claim 3, wherein the applied electric field is sinusoidal and the amplitude and phase of the frequency dependent electrophoretic mobility is calculated from the measurement of the amplitude and phase of the acoustic wave relative to the amplitude and phase of the applied electric field.
Claim 8
Dependent Claim
49 words
The method of claim 4, wherein the applied mechanical force is sinusoidal and the amplitude and phase of the frequency dependent electrophoretic mobility is calculated from the measurement of the amplitude and phase of the currents or voltages relative to the amplitude and phase of the applied mechanical force.
Claim 9
Dependent Claim
11 words
The method of claim 1, wherein the fluid is a liquid.
Claim 10
Independent Claim
96 words
A method for determining the particle charge and size distribution of particles in suspensions of arbitrary concentration in a fluid medium, comprising: applying an unsteady electric field of at least two different frequencies to the suspension to accelerate the particles; measuring a resulting acoustic wave generated by the particles as a result of the application at each frequency of unsteady electric field; determining the frequency dependent electrophoretic mobility of the particles from the measured acoustic wave at each of the applied frequencies; and calculating the particle size and charge distribution from the frequency dependent electrophoretic mobility.
Claim 11
Independent Claim
96 words
A method for determining the particle charge and size distribution of particles in suspensions of arbitrary concentration in a fluid medium, comprising: applying an unsteady electric field of at least two different frequencies to the suspension to accelerate the particles; measuring a resulting acoustic wave generated by the particles as a result of the application at each frequency of unsteady electric field; determining the frequency dependent electrophoretic mobility of the particles from the measured acoustic wave at each of the applied frequencies; and calculating the particle size and charge distribution from the frequency dependent electrophoretic mobility.
Claim 12
Independent Claim
96 words
A method for determining the particle charge and size distribution of particles in suspensions of arbitrary concentration in a fluid medium, comprising: applying an unsteady mechanical force of at least two different frequencies to the suspension to accelerate the particles; measuring a resulting electrical response generated by the particles as a result of the application at each frequency of unsteady mechanical force; determining the frequency dependent electrophoretic mobility of the particles from the measured electrical response at each of the applied frequencies; and calculating the particle size and charge distribution from the frequency dependent electrophoretic mobility.
Claim 13
Independent Claim
96 words
A method for determining the particle charge and size distribution of particles in suspensions of arbitrary concentration in a fluid medium, comprising: applying an unsteady mechanical force of at least two different frequencies to the suspension to accelerate the particles; measuring a resulting electrical response generated by the particles as a result of the application at each frequency of unsteady mechanical force; determining the frequency dependent electrophoretic mobility of the particles from the measured electrical response at each of the applied frequencies; and calculating the particle size and charge distribution from the frequency dependent electrophoretic mobility.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1994-10-21 | 1995-04-22 | 1995-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-10-21 | 1999-04-22 | 1999-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-10-21 | 2003-04-22 | 2003-10-22 | $7700.00 | Window Closed / Lapsed |