US4794086A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for measurement of impurities in liquids
Assignee: Liquid Air Corp
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Filing: 1985-11-25
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Granted: 1988-12-27
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Expires: 2005-11-25
Abstract
Abstract Method and apparatus for the measurement of sub-ppm concentrations of impurities in liquids. The liquid to be measured for impurities is dispersed into uniform droplets of a precisely known diameter D in a gas stream, such as air, using for example, a vibratory orifice generator. The dispersed droplets evaporate in the gas stream to leave a residue particle having a diameter d, which can be measured for example by means of a laser light scattering spectrometer. The concentration by volume, C v , of the impurities can then be calculated according to the equation; C v =(d/D) 3 .
Inventors
- 👤 Gerhard Kasper
- 👤 Horng Y. Wen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 03:49
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/18; G01N15/00; G01N15/06; G01N15/02; G01N15/0205; G01N15/065; G01N21/00; G01N21/84; G01N21/85; G01N2021/8557; G01N2021/8564; Y; Y10; Y10T; Y10T436/00; Y10T436/25; Y10T436/25875
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
96 words
A method for the rapid measurement of the concentration by volume of sub-ppm levels of dissolved impurities in a liquid comprising: providing a liquid containing dissolved impurities; dispersing said liquid in a gas stream to generate uniform droplets of precisely known diameter D; evaporating said droplets while they are carried in said gas stream so that each droplet leaves a residue particle having a diameter d; measuring the diameter d of the residue particles; and calculating the concentration by volume, C v , of the dissolved impurities in the liquid according to the equation: C.sub.v =(d/D).sup.3.
Claim 2
Independent Claim
96 words
A method for the rapid measurement of the concentration by volume of sub-ppm levels of dissolved impurities in a liquid comprising: providing a liquid containing dissolved impurities; dispersing said liquid in a gas stream to generate uniform droplets of precisely known diameter D; evaporating said droplets while they are carried in said gas stream so that each droplet leaves a residue particle having a diameter d; measuring the diameter d of the residue particles; and calculating the concentration by volume, C v , of the dissolved impurities in the liquid according to the equation: C.sub.v =(d/D).sup.3.
Claim 3
Dependent Claim
26 words
The method as claimed in claim 1 wherein: the diameter D of said droplets is in the range of about 20 um to about 50 um.
Claim 4
Dependent Claim
112 words
The method as claimed in claim 1 wherein: any static charges on the droplets and residue particles are neutralized before measuring the diameter d of the residue particles and wherein said liquid is dispersed in said gas stream using a monodisperse droplet generator wherein a jet of said liquid fed by a syringe pump is broken up in a controlled manner into highly uniform droplets of precisely known diameter D by a piezoelectric vibrating orifice which vibrates at a selectable frequency and said droplets are introduced into a turbulent gas stream of said gas, which gas is substantially non-reactive with the liquid or dissolved impurities to disperse and rapidly dry said droplets.
Claim 5
Independent Claim
29 words
The method as claimed in claims 1 or 3 wherein: the diameter D of said droplets is (one) in the range of about 1 um to about 200 um.
Claim 6
Dependent Claim
24 words
The method as claimed in claim 1 or 3 wherein the diameter d of said residue particles is measured with an aerodynamic particle sizer.
Claim 7
Dependent Claim
22 words
The method as claimed in claim 3 wherein: said gas stream is filtered prior to its passage through said monodisperse droplet generator.
Claim 8
Dependent Claim
27 words
The method as claimed in claim 1 or 3 wherein: the diameter d of said residue particles is measured using an electrostatic classifier and a particle detector.
Claim 9
Dependent Claim
16 words
The method as claimed in claim 7 wherein said particle detector is a condensation nuclei counter.
Claim 10
Dependent Claim
45 words
The method as claimed in claim 3 wherein: any static charge on said droplets and said residue particles are neutralized electrically by a krypton-85 radioactive neutralizer to reduce the level of static charge on said droplets and said residue particles to near Boltzmann charge equilibrium.
Claim 11
Dependent Claim
64 words
The method as claimed in claim 9 further comprising: periodically heating said gas stream carrying said residue particles to cause evaporation of dissolved organic impurities in said residue particles to enable a determination of whether organic or inorganic dissolved impurities are present in said liquid by comparing the diameter d of said particles before heating with the diameter d of said particles after heating.
Claim 12
Dependent Claim
24 words
The method as claimed in claim 3 or 9 wherein: the diameter d of said residue particles is measured using a light scattering spectrometer.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-12-27 | 1992-06-27 | 1992-12-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-12-27 | 1996-06-27 | 1996-12-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-12-27 | 2000-06-27 | 2000-12-27 | $7700.00 | Window Closed / Lapsed |