US3668382A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Separation and detection of trace substances in gaseous samples containing moisture by diluting with dry air
Assignee: PCP Inc A CORP OF FLORIDA
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Filing: 1968-11-26
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Granted: 1972-06-06
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Expires: 1988-11-26
Abstract
Abstract Apparatus and methods for sorting and detecting trace gases which undergo ion-molecule reactions and for reducing the deleterious effects of moisture upon the measurements. Positive or negative ions of the trace gas are formed by ion-molecule reactions between molecules of the trace gas and primary ions from another gas. Ions are classified in accordance with their velocity in an electric drift field. The effects of moisture in the sample are significantly reduced by diluting the sample with dry air, which is recirculated after treatment.
Inventors
- 👤 Martin J Cohen
- 👤 Roger F Wernlund
- 👤 David I Carroll
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 07:40
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/62; G01N27/622
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
91 words
A method of detecting a substance in a gaseous sample containing a substantial quantity of moisture interferant, which comprises diluting the sample by adding dry gas thereto substantially devoid of trace material until the partial pressure of the moisture interferant is of the order of 2 Torr or less, forming ions from the sample including ions of the said substance, by ion-molecule reactions, applying a drift field to said ions, and detecting ions having a predetermined velocity, in said field, said forming and field-applying steps being performed at substantially atmospheric pressure.
Claim 2
Dependent Claim
52 words
A method in accordance with claim 2, in which the detecting is accomplished by selectively gating a group of said ions to a first region at a predetermined time, and at a predetermined time thereafter selectively gating a portion of said group from said first region to means for detecting said portion.
Claim 3
Dependent Claim
22 words
A method in accordance with claim 2, in which said gaseous sample comprises air and in which said dry gas is air.
Claim 4
Dependent Claim
26 words
A method in accordance with claim 2, and in which the sample is diluted until the relative humidity of the sample is 10 percent or less.
Claim 5
Independent Claim
106 words
A method of reducing the effects of moisture upon ion-velocity-dependent measurements in a drift cell, which comprises mixing a sample of moisture-containing gas and trace-substance-containing gas to be analyzed in said drift cell with dry gas substantially free of said trace substance, feeding said mixture to said cell, forming ions from said mixture for analysis in said cell, exhausting the remainder of said mixture from said cell, removing any trace substance in the exhaust from said cell, dehydrating the exhaust from said cell, and utilizing the resultant dehydrated exhaust free of said trace substance to mix with a new sample to be analyzed in said cell.
Claim 6
Dependent Claim
131 words
Apparatus for detecting the presence of a substance in a gaseous sample in the presence of substantial quantities of water vapor, which comprises an envelope having a gas inlet to which said sample is fed, means for forming ions from said sample in said envelope by ion-molecule reactions, means for applying a drift field to the ions in said envelope, means for producing an electrical output from said envelope in accordance with the velocity of predetermined ions in said drift field, means for mixing said gaseous sample with dry gas substantially free of said substance before said sample is fed to said inlet and until the partial pressure of said water vapor is of the order of 2 Torr or less, and means for maintaining substantially atmospheric Pressure in said envelope.
Claim 7
Dependent Claim
17 words
Apparatus in accordance with claim 7, further comprising means for heating said envelope and said mixing means.
Claim 8
Dependent Claim
18 words
Apparatus in accordance with claim 8, wherein said envelope and said mixing means are surrounded by thermal insulation.
Claim 9
Dependent Claim
13 words
Apparatus in accordance with claim 7, wherein said mixing means comprises a venturi.
Claim 10
Dependent Claim
113 words
Apparatus for detecting the presence of a substance in a gaseous sample, which comprises an envelope having a gas inlet to which said sample is fed, means for forming ions from said sample in said envelope, means for applying a drift field to the ions in said envelope, means for producing an electrical output from said envelope in accordance with the velocity of predetermined ions in said drift field, and means for mixing said gaseous sample with dry gas substantially free of said substance before said sample is fed into said inlet, said envelope having a gas outlet connected to said mixing means in a recirculation loop containing means for removing said substance.
Claim 11
Dependent Claim
14 words
Apparatus in accordance with claim 11, wherein the last-mentioned means includes a molecular sieve.
Claim 12
Dependent Claim
13 words
Apparatus in accordance with claim 11, wherein said recirculation loop contains dehydrating means.
Claim 13
Dependent Claim
16 words
Apparatus in accordance with claim 11, wherein said recirculation loop includes means for forcing gas therethrough.
Claim 14
Dependent Claim
19 words
Apparatus in accordance with claim 11, wherein said recirculation loop has means for venting excess gas to the atmosphere.
References Cited (Backward Citations)
US3355587A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-06 | 1975-12-06 | 1976-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-06 | 1979-12-06 | 1980-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-06 | 1983-12-06 | 1984-06-06 | $7700.00 | Window Closed / Lapsed |