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US 4,652,755 AGranted
Method and apparatus for analyzing particle-containing gaseous suspensions
AssigneeAdvanced Fuel Research, Inc.
InventorsPeter R. Solomon, Robert M. Carangelo, Philip E. Best
Life of this patent
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Abstract
The method and apparatus permit analyses, by optical means, of properties of gaseous suspensions of particles, by measuring radiation that is emitted, transmitted or scattered by the particles. Determinations of composition, size, temperature and spectral emittance can be performed either in-situ or by sampling, and Fourier-transform infrared spectrometric techniques are most effectively used. Apparatus specifically adapted for performing radiation scattering analyses, and for collecting radiation from different sources, are provided.
Claims59
In apparatus for the analysis of a gaseous suspension of liquid particles, solid particles, or both, the combination comprising:
- (a) interferometer means operatively positionable with respect to the suspension for encoding radiation projected thereinto and radiation emanating therefrom;
- (b) means operatively positionable with respect to the suspension and said interferometer means for collecting coded radiation from the suspension, said collecting means being adapted to discriminate radiation transmitted through the suspension from radiation emanating therefrom, such emanating radiation including any radiation scattered by the particles;
- (c) source means for providing an electromagnetic radiation beam and for projecting it through said interferometer means for coding thereby and for transmission through the suspension;
- and
- (d) electronic data processing means for analyzing the radiation collected by said collecting means.
2 more elements
In apparatus for the analysis of a gaseous suspension of liquid particles, solid particles, or both, utilizing refracted components of radiation, the combination comprising:
- (a) containment means having a sidewall defining a chamber for the flow of a gaseous suspension of particles along a path therethrough, at least one port being provided in said sidewall to provide optical access to said path;
- (b) source means for providing electromagnetic radiation directed inwardly from substantially all peripheral points about said path;
- and
- (c) means for collecting radiation emanating from said containment means, said containment means, source means and collecting means being so adapted that components of radiation emanating from said source means that have been diverted from their original paths due to interaction with the particles of the suspension can be substantially discriminated from radiation that has not been so diverted.
1 more element
In a method for the analysis of at least one parameter of a gaseous suspension of liquid or solid particles, or both, the steps comprising:
- a. providing a gaseous suspension of particles;
- b. causing electromagnetic radiation from at least one source to impinge upon said suspension;
- c. collecting spectral radiation from said so irradiated suspension;
- d. developing a spectrum representative of the intensity of the collected radiation as a function of wavenumber;
- and
- e. comparing said representative spectrum to preestablished spectra indicative of the parameter for which said suspension is being analyzed, and fitting said representative spectrum thereto to determine said parameter, said comparison being made by application of the basic equation, or equations derived therefrom:
- ##EQU11## wherein "y" is the integral:
- ##EQU12## and wherein:
- E - represents any collected radiation emanating from said gaseous suspension and not transmitted therethrough,
- k.sub.s and k.sub.g - are the extinction coefficients for any soot present and the gas phases, respectively, of the suspension,
- BB(T.sub.s), BB(T.sub.g), BB(T.sub.p), and BB(T.sub.w) - are the black-body spectra appropriate to the temperature of any soot present, the gas, the particles, and the medium surrounding said suspension, respectively,
- N - is the number density of the particles in the suspension,
- A - is the geometric cross-sectional area of said particles,
- L - is the effective path length through the gaseous suspension, and dl is the width of a theoretical slice at position 1 therealong,
- .epsilon. - is the spectral emmittance of the particles,
- Q.sub.s - is the ratio of the radiation scattering cross section to the geometric cross section of the particles, and
- Q.sub.ext - is the ratio of the extinction cross section to the geometric cross section of said particles, and is equal to Q.sub.s +Q.sub.abs, Q.sub.abs being the ratio of the absorption cross section to the geometric cross section of the particles, and wherein the foregoing quantities, other than N, A and L, are wavenumber dependent.
14 more elements
In a method for the analysis of at least one parameter of a gaseous suspension of liquid or solid particles, or both, the steps comprising:
- a. causing a beam of electromagnetic radiation to impinge upon the suspension to be analyzed;
- b. collecting radiation transmitted through and emanating from said so irradiated suspension;
- c. distinguishing said transmitted radiation from said emanating radiation;
- d. developing spectra representative of the intensity of the transmitted and emanating radiation collected and distinguished in said steps b. and c., as functions of wavenumber;
- and
- e. comparing said representative spectra to preestablished spectra indicative of a parameter for which said suspension is being analyzed, and fitting said representative spectra thereto to determine said parameter.
3 more elements
In a method for the quantitative compositional analysis of a gaseous suspension of liquid or solid particles, or both, the steps comprising:
- a. passing a gaseous suspension of particles to be analyzed into a chamber having at least one port for optical access thereinto;
- b. causing electromagnetic radiation from at least one source to impinge at off axis angles upon the particles of said suspension during passage through said chamber, said off-axis angles consisting essentially of angles oblique to said one access port;
- c. collecting through said one port radiation from said so irradiated particles, said collected radiation being limited, by virtue of said off-axis impingement, substantially to rays from said source refracted or otherwise diverted by said particles;
- d. developing a spectrum representative of the path and amplitude of said collected radiation as a function of wavenumber;
- and
- e. comparing said representative spectrum to preestablished spectra indicative of the compositional parameter for which said suspension is being analyzed, and fitting said representative spectrum thereto to determine said parameter.
3 more elements
In a method for the analysis of particle size in a gaseous suspension of liquid or solid particles, or both, the steps comprising:
- a. providing a substantially homogeneous gaseous suspension of particles;
- b. causing a beam of electromagnetic radiation to impinge upon said suspension;
- c. selectively collecting radiation transmitted through said so irradiated suspension;
- d. developing a spectrum representative of the intensity of the collected radiation as a function of wavenumber;
- and
- e. comparing said representative spectrum to preestablished spectra indicative of particle size, and fitting said representative spectrum thereto to determine a particle size parameter, said representative spectrum being that of (1-.tau.) and said comparison being made based upon the formula:
- (1-.tau.)=1-exp[-(k.sub.s +k.sub.g +NAQ.sub.ext)L]
- wherein:
- k.sub.s and k.sub.g - are the extinction coefficients for any soot present and the gas phase, respectively, of said suspension,
- N - is the number density of said particles in said suspension,
- A - is the geometric cross-sectional area of said particles,
- L - is the effective path length through said gaseous suspension, and
- Q.sub.ext - is the ratio of the extinction cross section to the geometric cross section of said particles, and is equal to Q.sub.s +Q.sub.abs, Q.sub.abs being the ratio of the absorption cross section to the geometric cross section of said particles, and Q.sub.s being the ratio of the radiation scattering cross section to the geometric cross section of said particles, the quantities other than N, A and L being wavenumber dependent.
10 more elements
Dependencies are inferred from the claim text.