US4837440A
Expired / Lapsed
US
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Method and apparatus for characterization of aerosols
Assignee: MATTER & SIEGMANN AG A CORP OF SWITZERLAND
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Filing: 1986-11-03
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Granted: 1989-06-06
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Expires: 2006-11-03
Abstract
Abstract Aerosol particles, resulting from the combustion of organic substances with insufficient oxygen supply, usually contain toxic, higher hydrocarbonic substances (e.g. tar) on their surface. These substances, e.g. tar, has the property to be photoelectrically more active than other substances contained in the atmosphere. In the method and apparatus according to the invention an aerosol, i.e. the carrier gas containing the particles to be characterized, is used which has been brought to at least one predetermined temperature sufficient for evaporation or decomposition or preventing condensation of molecules on particles of said aerosol that quench or enhance photoelectric activity. Such aerosol is exposed to electromagnetic radiation and, thereby, activated to electron emission. Thereafter the charge of the photoelectrically positively charged particles is determined by means of size selective filter means which are connected to current or charge measuring equipment. From the measured values information can be derived about the nature and amount of said molecules and about the remaining surface of the aerosol particles. Additional information on the coatings and also on the species of hydrocarbon may be obtained by observing the measured values as a function of temperature. The method and apparatus are particularly useful for the measurement of air pollution.
Inventors
- 👤 Heinz Burtscher
- 👤 Adnreas Schmidt-Otl
- 👤 Hans-Christoph Siegmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:51
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/62; G01N27/64; G01N27/66
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
75 words
A method for the characterization of particles in aerosol, comprising: using an aerosol, which has been brought to at least one predetermined temperature sufficient for evaporation or decomposition or preventing condensation of molecules on particles of said aerosol; exposing said aerosol to an electromagnetic radiation for activating particles contained in the aerosol to cause said aerosol particles to emit electrons and attain an electric charge correspondingly; and measuring the electric charge of said aerosol particles.
Claim 2
Independent Claim
75 words
A method for the characterization of particles in aerosol, comprising: using an aerosol, which has been brought to at least one predetermined temperature sufficient for evaporation or decomposition or preventing condensation of molecules on particles of said aerosol; exposing said aerosol to an electromagnetic radiation for activating particles contained in the aerosol to cause said aerosol particles to emit electrons and attain an electric charge correspondingly; and measuring the electric charge of said aerosol particles.
Claim 3
Independent Claim
104 words
A method for the quantitative and qualitative characterization of hydrocarbon containing particles in an aerosol, comprising: using an aerosol, which has been brought to at least one predetermined temperature sufficient for evaporation or decomposition or preventing condensation of molecules on particles of said aerosol; exposing said aerosol to an electromagnetic radiation having photon energies which are below the ionization energy of the carrier gas of the aerosol and above the work function of said aerosol particles for activating said aerosol particles to cause said aerosol particles to emit electrons and attain an electric charge corresponsingly; and measuring said electric charge of said aerosol particles.
Claim 4
Independent Claim
104 words
A method for the quantitative and qualitative characterization of hydrocarbon containing particles in an aerosol, comprising: using an aerosol, which has been brought to at least one predetermined temperature sufficient for evaporation or decomposition or preventing condensation of molecules on particles of said aerosol; exposing said aerosol to an electromagnetic radiation having photon energies which are below the ionization energy of the carrier gas of the aerosol and above the work function of said aerosol particles for activating said aerosol particles to cause said aerosol particles to emit electrons and attain an electric charge corresponsingly; and measuring said electric charge of said aerosol particles.
Claim 5
Dependent Claim
14 words
Method according to claim 1, wherein ultraviolet radiation is used for activating aerosol particles.
Claim 6
Dependent Claim
34 words
Method according to claim 1, in which said aerosol is exposed to said radiation, while being at a temperature sufficient for evaporation or decomposition or preventing condensation of molecules on particles of said aerosol.
Claim 7
Dependent Claim
41 words
Method according to claim 1, in which a flow of said aerosol with a predetermined flow rate is established and subjected to heating and said activating radiation, and said charge measuring being carried out under stationary temperature conditions in the aerosol.
Claim 8
Dependent Claim
43 words
Method according to claim 1, in which said aerosol is heated in consecutive processing stages to a plurality of temperature levels, wherein each such processing stage comprises activating aerosol particles to electron emission and measuring the electric charge of the particles thus achieved.
Claim 9
Dependent Claim
44 words
Method according to claim 1, in which said aerosol is heated so as to create an at least temporarily continuous temperature increase, the rising rate of which is held below a limit value sufficiently low for establishing approximately stationary values in said charge measuring.
Claim 10
Dependent Claim
27 words
Method according to claim 1, in which said molecules to be evaporated, decomposed or prevented from condensation are capable of quenching the photoelectric activity of said particles.
Claim 11
Dependent Claim
15 words
Method according to claim 8, in which said molecules are non-aromatic hydrocarbons or derivates thereof.
Claim 12
Dependent Claim
12 words
Method according to claim 8, in which said molecules are inorganic acids.
Claim 13
Dependent Claim
11 words
Method according to claim 8, in which said molecules are water.
Claim 14
Dependent Claim
27 words
Method according to claim 1, in which said molecules to be evaporated, decomposed or prevented from condensation are capable of enhancing the photoelectric activity of said particles.
Claim 15
Dependent Claim
15 words
Method according to claim 12, in which said molecules are aromatic hydrocarbons or derivates thereof.
Claim 16
Independent Claim
291 words
An apparatus for characterization of particles in an aerosol, said apparatus comprising: an essentially closed chamber comprising a gas inlet, a gas outlet, and means for establishing an aerosol flow through said chamber; means mounted in the interior of said essentially closed chamber in the region of said inlet for electrically neutralizing said aerosol; means for heating said aerosol, said heating means comprising measuring and control means for establishing a predetermined aerosol temperature; radiation means arranged within the interior of said essentially closed chamber and defining an irradiation zone for activating the heated aerosol flowing therethrough; said irradiation zone comprising a wall surface held at a defined electric potential and having a conductivity which is high enough to conduct the charge of ions produced by irradiation and movable to said wall surface to said defined electric potential; and at least one collector electrode mounted in the interior of said essentially closed chamber downstream of said irradiation zone for collecting electrically charged particles and electrically connected to a current or charge meter; said at least one collector electrode comprising a size selective particle filter mounted downstream of said irradiation zone and arranged in the flow of said aerosol, said size selective particle filter comprising an electric capacitor having two electrodes in spaced relationship and an electric field between said two electrodes, said aerosol flowing through the space between said two electrodes and said electric field having a magnitude which is high enough to deposit at least a part of the charged particles of said aerosol on the negative electrode of said capacitor, and control means connected to said electrodes of said capacitor in order to periodically change the field strength of said electric field between a lower value and a higher value.
Claim 17
Independent Claim
291 words
An apparatus for characterization of particles in an aerosol, said apparatus comprising: an essentially closed chamber comprising a gas inlet, a gas outlet, and means for establishing an aerosol flow through said chamber; means mounted in the interior of said essentially closed chamber in the region of said inlet for electrically neutralizing said aerosol; means for heating said aerosol, said heating means comprising measuring and control means for establishing a predetermined aerosol temperature; radiation means arranged within the interior of said essentially closed chamber and defining an irradiation zone for activating the heated aerosol flowing therethrough; said irradiation zone comprising a wall surface held at a defined electric potential and having a conductivity which is high enough to conduct the charge of ions produced by irradiation and movable to said wall surface to said defined electric potential; and at least one collector electrode mounted in the interior of said essentially closed chamber downstream of said irradiation zone for collecting electrically charged particles and electrically connected to a current or charge meter; said at least one collector electrode comprising a size selective particle filter mounted downstream of said irradiation zone and arranged in the flow of said aerosol, said size selective particle filter comprising an electric capacitor having two electrodes in spaced relationship and an electric field between said two electrodes, said aerosol flowing through the space between said two electrodes and said electric field having a magnitude which is high enough to deposit at least a part of the charged particles of said aerosol on the negative electrode of said capacitor, and control means connected to said electrodes of said capacitor in order to periodically change the field strength of said electric field between a lower value and a higher value.
Claim 18
Independent Claim
178 words
An apparatus for characterization of particles in an aerosol, said apparatus comprising: an essentially closed chamber comprising a gas inlet, a gas outlet, and means for establishing an aerosol flow through said chamber; means mounted in the interior of said essentially closed chamber in the region of said inlet for electrically neutralizing said aerosol; means for bringing said aerosol to at least one predetermined temperature sufficient for evaporation or decomposition or preventing condensation of molecules on particles of said aerosol; radiation means arranged within the interior of said essentially closed chamber and defining an irradiation zone for activating the heated aerosol flowing therethrough; said irradiation zone comprising a wall surface held at a defined electric potential and having a conductivity which is high enough to conduct the charge of ions produced by irradiation and movable to said wall surface to said defined electric potential; and at least one collector electrode mounted in the interior of said essentially closed chamber downstream of said irradiation zone for collecting electrically charged particles and electrically connected to a current or charge meter.
Claim 19
Independent Claim
178 words
An apparatus for characterization of particles in an aerosol, said apparatus comprising: an essentially closed chamber comprising a gas inlet, a gas outlet, and means for establishing an aerosol flow through said chamber; means mounted in the interior of said essentially closed chamber in the region of said inlet for electrically neutralizing said aerosol; means for bringing said aerosol to at least one predetermined temperature sufficient for evaporation or decomposition or preventing condensation of molecules on particles of said aerosol; radiation means arranged within the interior of said essentially closed chamber and defining an irradiation zone for activating the heated aerosol flowing therethrough; said irradiation zone comprising a wall surface held at a defined electric potential and having a conductivity which is high enough to conduct the charge of ions produced by irradiation and movable to said wall surface to said defined electric potential; and at least one collector electrode mounted in the interior of said essentially closed chamber downstream of said irradiation zone for collecting electrically charged particles and electrically connected to a current or charge meter.
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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) | 1992-06-05 | 1992-12-05 | 1993-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-05 | 1996-12-05 | 1997-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-05 | 2000-12-05 | 2001-06-06 | $7700.00 | Window Closed / Lapsed |