Patent US3808433A successfully refreshed from Google Patents.
US3808433A
Expired / Lapsed
US
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Methods and apparatus for detection of very small particulate matter and macromolecules
Assignee: Individual
•
Filing: 1972-12-29
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Granted: 1974-04-30
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Expires: 1992-12-29
Abstract
Abstract A method and apparatus for detecting, sizing, and counting gas borne particulate matter are described. The particles are impacted onto a heated surface capable of pyrolyzing them. Some of the products of the pyrolysis are then surfaceionized, producing a burst of ions which is detected electronically producing a voltage pulse proportional to the amount of surfaceionizable matter originally present in the particle. Methods are described for adding to each particle an amount of surfaceionizable material proportional to the particle size, enabling the instrument to measure the particle size distribution of a collection of gasborne particles. The basic apparatus may detect particles by means of either positive or negative surfaceionization, and is capable of operation either when situated in air or when located in a vacuum system.
Inventors
- 👤 W Fite
- 👤 R Myers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 18:13
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/62; G01N27/626
Claims Analysis
Total Claims: 56
Claim 1
Independent Claim
50 words
A method of detecting a particle of dust, smoke and macromolecules of 1000 AMU or greater which comprises the steps of producing a burst of ions by inducing said particle to strike a heated surface and discerning the burst of ions so produced by the detection of its electrical charge.
Claim 2
Independent Claim
50 words
A method of detecting a particle of dust, smoke and macromolecules of 1000 AMU or greater which comprises the steps of producing a burst of ions by inducing said particle to strike a heated surface and discerning the burst of ions so produced by the detection of its electrical charge.
Claim 3
Dependent Claim
30 words
A method in accordance with claim 1 wherein at least part of said burst of ions comprises surface-ionizable atoms or molecules occurring as constitutents of said particle including impurities therein.
Claim 4
Dependent Claim
61 words
A method in accordance with claim 1 wherein said particle is caused to pass through a vapor of surface-ionizable atoms or molecules prior to striking said heated surface, said surface-ionizable atoms or molecules attaching to said particle, at least part of said burst of ions comprising ions produced from said surface-ionizable atoms or molecules by surface ionization at the heated surface.
Claim 5
Independent Claim
114 words
A method of determining the size of a particle of dust, smoke and other macromolecules of about 1,000 AMU or larger, of surface-ionizable atoms or molecules wherein some of said atoms or molecules are attached to said particle during its passage through the vapor in a number proportional to the size of said particle, causing said particle to strike a hot surface where said attached atoms or molecules are released and form a burst of ions, and detecting and measuring the electrical charge of said ions, the total amount of said electrical charge being proportional to the number of said attached surface-ionizable atoms or molecules and therefore indicative of the size of said particle.
Claim 6
Independent Claim
114 words
A method of determining the size of a particle of dust, smoke and other macromolecules of about 1,000 AMU or larger, of surface-ionizable atoms or molecules wherein some of said atoms or molecules are attached to said particle during its passage through the vapor in a number proportional to the size of said particle, causing said particle to strike a hot surface where said attached atoms or molecules are released and form a burst of ions, and detecting and measuring the electrical charge of said ions, the total amount of said electrical charge being proportional to the number of said attached surface-ionizable atoms or molecules and therefore indicative of the size of said particle.
Claim 7
Independent Claim
91 words
An apparatus for the detection of individual gasborne particles of dust, smoke and other macromolecules of 1,000 AMU or more which comprises ionization means which includes a heated surface in fluid communication with the gas containing and surrounding said particles, said surface adapted to receive said particles thereon and to produce a burst of ions through surface-ionization upon receiving one of said particles; and measuring means for performing the function of responding to the electric charge of said burst of ions including means for performing the function of registering said charge.
Claim 8
Independent Claim
91 words
An apparatus for the detection of individual gasborne particles of dust, smoke and other macromolecules of 1,000 AMU or more which comprises ionization means which includes a heated surface in fluid communication with the gas containing and surrounding said particles, said surface adapted to receive said particles thereon and to produce a burst of ions through surface-ionization upon receiving one of said particles; and measuring means for performing the function of responding to the electric charge of said burst of ions including means for performing the function of registering said charge.
Claim 9
Dependent Claim
56 words
An apparatus in accordance with claim 5 wherein said measuring means includes a second surface, said heated surface and said second surface being at different potentials whereby an electric field is created between said surfaces which is adapted to cause a burst of ions produced at said heated surface to be accelerated to said second surface.
Claim 10
Dependent Claim
65 words
An apparatus in accordance with claim 5, comprising means for creating an electric field wherein said heated surface is locateD in said electric field, said electric field being of such an intensity that the production of burst of ions at the heated surface initiates electrical breakdown of the carrier gas, said breakdown producing an additional number of ions, said ions being detected by said means.
Claim 11
Dependent Claim
54 words
An apparatus in accordance with claim 5 wherein said heated surface is located in a cylinder through which the gas containing and surrounding the particles, means being associated with said cylinder for inducing said gas to move at a speed sufficiently high that said particles are impact with high efficiency onto said heated surface.
Claim 12
Dependent Claim
65 words
An apparatus in accordance with claim 8 comprising means for creating an electric field wherein said heated surface is located in said electrical field, said electrical field being of such an intensity that the production of burst of ions at the heated surface initiates electrical breakdown of the carrier gas, said breakdown producing an additional number of ions, said ions being detected by said means.
Claim 13
Dependent Claim
51 words
An apparatus in accordance with claim 5 wherein said measuring means comprises a pulse height discriminator adapted to separate small pulses caused by surface-ionizable impurities in the material of the heated surface from more intense pulses caused by said ions produced at said heated surface upon being struck by said particles.
Claim 14
Dependent Claim
29 words
An apparatus in accordance with claim 5 wherein said heated surface is composed of a metal in the group consisting of tungsten, iridium, platinum, tantalum, molybdenum, rhenium and gold.
Claim 15
Dependent Claim
25 words
An apparatus in accordance with claim 5 wherein a circuit is provided for passing current through said heated surface for causing it to become heated.
Claim 16
Dependent Claim
53 words
An apparatus in accordance with claim 5, wherein a further heated surface is included which is adapted to pyrolize said particles thereby producing surface-ionizable atoms, molecules or radicals which thereafter strike said first-mentioned heated surface, where some of said atoms, molecules or radicals become surface-ionized, said ions being detected by said registration means.
Claim 17
Dependent Claim
24 words
An apparatus in accordance with claim 13 wherein the temperature of said first-heated surface is higher than the temperature of said further heated surface.
Claim 18
Independent Claim
121 words
An apparatus for the detection of particles of dust, smoke and other macromolecules of 1,000 AMU or more which comprises a vacuum chamber with a small aperture opening to the gas containing and surrounding said particles, means for continuously exhausting said vacuum chamber, the capacity of said exhaust means and the size of said small aperture being such that the chamber is maintained at a pressure substantially less than atmospheric pressure, a heated surface within said vacuum chamber located to receive particles therein and adapted to produce a burst of ions upon being struck by one of said particles in said vacuum chamber, and measuring means for performing the function of registering said bursts of ions produced at said heated surface.
Claim 19
Independent Claim
121 words
An apparatus for the detection of particles of dust, smoke and other macromolecules of 1,000 AMU or more which comprises a vacuum chamber with a small aperture opening to the gas containing and surrounding said particles, means for continuously exhausting said vacuum chamber, the capacity of said exhaust means and the size of said small aperture being such that the chamber is maintained at a pressure substantially less than atmospheric pressure, a heated surface within said vacuum chamber located to receive particles therein and adapted to produce a burst of ions upon being struck by one of said particles in said vacuum chamber, and measuring means for performing the function of registering said bursts of ions produced at said heated surface.
Claim 20
Dependent Claim
15 words
An apparatus in accordance with claim 15 wherein said measuring means includes an electron multiplier.
Claim 21
Dependent Claim
53 words
An apparatus in accordance with claim 15 wherein said measuring means comprises a pulse height discriminator adapted to separate small pulses caused by surface-ionizable impurities in the material of the heated surface from more intense pulses caused by said burst of ions produced at said heated surface upon being struck by said particles.
Claim 22
Dependent Claim
53 words
An apparatus in accordance with claim 15 wherein a further heated surface is included which is adapted to pyrolize said particles thereby producing surface-ionizable atoms, molecules or radicals which thereafter strike said first-mentioned heated surface, where some of said atoms, molecules or radicals become surface-ionized, said ions being detected by said registration means.
Claim 23
Dependent Claim
24 words
An apparatus in accordance with claim 18 wherein the temperature of said first-heated surface is higher than the temperature of said further heated surFace.
Claim 24
Dependent Claim
25 words
An apparatus in accordance with claim 15 wherein a circuit is provided for passing current through said heated surface for causing it to become heated.
Claim 25
Dependent Claim
29 words
An apparatus in accordance with claim 15, wherein said heated surface is composed of a metal in the group consisting of tungsten iridium, platinum, tantalum, molybdenum, rhenium and gold.
Claim 26
Dependent Claim
21 words
An apparatus in accordance with claim 15 wherein said measuring means includes means for separating ions according to their charge-to-mass ratio.
Claim 27
Dependent Claim
23 words
An apparatus in accordance with claim 22, wherein said means for separating ions according to their charge-to-mass ratio is a quadrupole mass filter.
Claim 28
Independent Claim
188 words
An apparatus for the detection of particles of dust, smoke and other macromolecules of 1,000 AMU or more which comprises a first vacuum chamber with a small aperture opening to the gas containing and surrounding said particles and a small opening to a second vacuum chamber, said aperture and said opening being aligned, means for continuously exhausting both said vacuum chambers in a differential pumping arrangement, the capacity of said exhaust means and the sizes of said aperture and said opening being such that said first vacuum chamber is maintained at a pressure substantially less than atmospheric pressure and that said second vacuum chamber is maintained at a pressure substantially less than the pressure in said first vacuum chamber, a heated surface within said second vacuum chamber located to receive particles that pass in a substantially straight line through said aperture and said opening and enter the second chamber, said surface being adapted to produce a burst of ions upon being struck by one of said particles, and measuring means responsive to said burst of ions including means for registering burst of ions produced at said heated surface.
Claim 29
Independent Claim
188 words
An apparatus for the detection of particles of dust, smoke and other macromolecules of 1,000 AMU or more which comprises a first vacuum chamber with a small aperture opening to the gas containing and surrounding said particles and a small opening to a second vacuum chamber, said aperture and said opening being aligned, means for continuously exhausting both said vacuum chambers in a differential pumping arrangement, the capacity of said exhaust means and the sizes of said aperture and said opening being such that said first vacuum chamber is maintained at a pressure substantially less than atmospheric pressure and that said second vacuum chamber is maintained at a pressure substantially less than the pressure in said first vacuum chamber, a heated surface within said second vacuum chamber located to receive particles that pass in a substantially straight line through said aperture and said opening and enter the second chamber, said surface being adapted to produce a burst of ions upon being struck by one of said particles, and measuring means responsive to said burst of ions including means for registering burst of ions produced at said heated surface.
Claim 30
Dependent Claim
25 words
An apparatus in accordance with claim 24 wherein a circuit is provided for passing current through said heated surface for causing it to become heated.
Claim 31
Dependent Claim
55 words
An apparatus in accordance with claim 24 wherein said measuring means comprises a pluse height discriminator adapted to separate small pulses caused by surface-ionizable impurities in the material of the heated surface from more intense pulses caused by said burst of ions produced at said heated surface upon being struck by one of said particles.
Claim 32
Dependent Claim
29 words
An apparatus in accordance with claim 24 wherein said heated surface is composed of a metal in the group consisting of tungsten, iridium, platinum, tantalum, molybdenum, rhenium and gold.
Claim 33
Dependent Claim
15 words
An apparatus in accordance with claim 24 wherein said measuring means includes an electron multiplier.
Claim 34
Dependent Claim
30 words
An apparatus according to claim 24 wherein one of the vacuum chambers other than said second vacuum chamber contains means for producing therein a vapor of surface-ionizable atoms or molecules.
Claim 35
Dependent Claim
32 words
An apparatus in accordance with claim 29 wherein said vapor is composed of an organic compound from which positive ions of organic radicals or the negative ion CN is produced by surface-ionization.
Claim 36
Dependent Claim
27 words
An apparatus in accordance with claim 29 wherein said vapor is composed of an alkali metal in the group consisting of lithium, sodium, potassium, rubidium and cesium.
Claim 37
Dependent Claim
40 words
An apparatus in accordance with claim 29 wherein said vapor is composed of a compound containing halogen atoms in the group consisting of fluorine, chlorine, bromine and iodine, or molecules in the group consisting of fluorine, chlorine, bromine and iodine.
Claim 38
Dependent Claim
28 words
An apparatus in accordance with claim 29 including means for producing said vapor in the form of an atomic or molecular beam across which said particles must pass.
Claim 39
Dependent Claim
51 words
An apparatus in accordance with claim 24 wherein a further heated surface is included which is adapted to pyrolize said particles producing surface-ionizable atoms, molecules or radicals which thereafter strike first-mentioned heated surface, where some of said atoms, molecules or radicals become surface-ionized, said ions being detected bY said registration means.
Claim 40
Dependent Claim
24 words
An apparatus in accordance with claim 34 wherein the temperature of said first-heated surface is higher than the temperature of said further heated surface.
Claim 41
Dependent Claim
21 words
An apparatus in accordance with claim 24 wherein said measuring means includes means for separating ions according to their charge-to-mass ratio.
Claim 42
Dependent Claim
23 words
An apparatus in accordance with claim 36 wherein said means for separating ions according to their charge-to-mass ratio is a quadrupole mass filter.
Claim 43
Dependent Claim
39 words
An apparatus in accordance with claim 24 in which one or more vacuum chambers and means for exhausting said vacuum chambers are placed intermediate between said first vacuum chamber and said second vacuum chambers, in a differential pumping arrangement.
Claim 44
Dependent Claim
55 words
An apparatus in accordance with claim 38 wherein said measuring means comprises a pulse height discriminator adapted to separate small pulses caused by surface-ionizable impurities in the material of the heated surface from more intense pulses caused by said burst of ions produced at said heated surface upon being struck by one of said particles.
Claim 45
Dependent Claim
29 words
An apparatus in accordance with claim 38 wherein said heated surface is composed of a metal in the group consisting of tungsten, iridium, platinum, tantalum, molybdenum, rhenium and gold.
Claim 46
Dependent Claim
25 words
An apparatus in accordance with claim 38 wherein a circuit is provided for passing current through said heated surface for causing it to become heated.
Claim 47
Dependent Claim
15 words
An apparatus in accordance with claim 38 wherein said measuring means includes an electron multiplier.
Claim 48
Dependent Claim
53 words
An apparatus in accordance with claim 38 wherein a further heated surface is included which is adapted to pyrolize said particles thereby producing surface-ionizable atoms, molecules or radicals which thereafter strike said first-mentioned heated surface, where some of said atoms, molecules or radicals become surface-ionized, said ions being detected by said registration means.
Claim 49
Dependent Claim
24 words
An apparatus in accordance with claim 43 wherein the temperature of said first-heated surface is higher than the temperature of said further heated surface.
Claim 50
Dependent Claim
21 words
An apparatus in accordance with claim 38 wherein said measuring means includes means for separating ions according to their charge-to-mass ratio.
Claim 51
Dependent Claim
23 words
An apparatus in accordance with claim 45 wherein said means for separating ions according to their charge-to-mass ratio is a quadrupole mass filter.
Claim 52
Dependent Claim
31 words
An apparatus in accordance with claim 38 wherein one of the vacuum chambers other than said second vacuum chamber contains means for producing therein a vapor of surface-ionizable atoms or molecules.
Claim 53
Dependent Claim
32 words
An apparatus in accordance with claim 47, wherein said vapor is composed of an organic compound from which positive ions of organic radicals or the negative ion CN is produced by surface-ionization.
Claim 54
Dependent Claim
28 words
An apparatus in accordance with claim 47 including means for producing said vapor in the form of an atomic or molecular beam across which said particles must pass.
Claim 55
Dependent Claim
41 words
An apparatus in accordance with claim 47 wherein said vapor is composed of molecules or compounds containing halogen atoms in the group consisting of fluorine, chlorine, bromine and iodine, or molecules of the group consisting of fluorine, chlorine, bromine, and iodine.
Claim 56
Dependent Claim
27 words
An apparatus in accordance with claim 47 wherein said vapor is composed of an alkali metal in the group consisting of lithium, sodium, potassium, rubidium and cesium.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-04-29 | 1977-10-29 | 1978-04-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-04-29 | 1981-10-29 | 1982-04-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-04-29 | 1985-10-29 | 1986-04-30 | $7700.00 | Window Closed / Lapsed |