US4388272A
Expired / Lapsed
US
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Method and apparatus for precise control of vapor phase concentrations of volatile organics
Assignee: Northwestern University
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Filing: 1981-04-08
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Granted: 1983-06-14
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Expires: 2001-04-08
Abstract
Abstract A method and apparatus for precise control of vapor phase concentrations of volatile organic compounds is provided which utilize desorption of monolayers of the organic compound from a solid adsorbent. The method and apparatus can be used for measuring human olfactory system performance, for calibration of analytical chemical instruments, and in other applications.
Inventors
- 👤 Robert C. Gesteland
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 04:14
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/0004; G01N33/0006; G01N30/00; G01N33/48; G01N33/483; G01N33/497; G01N33/4972; Y; Y10; Y10T; Y10T436/00; Y10T436/10; Y10T436/100833
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
157 words
The method of providing a predetermined concentration of a volatile organic compound in a gas carrier sample, comprising: (a) applying the volatile organic compound free of any other volatile compound to a solid granular adsorbent to partially coat its adsorptive surfaces, the amount of said compound on said adsorbent being less the minimum amount capable of saturating a gas in contact therewith at an ambient temperature, said compound and said adsorbent being chemically non-reactive; (b) introducing said organic compound-containing adsorbent into an enclosed space from which gas samples can be selectively removed, said enclosed space containing a carrier gas in contact with said adsorbent at said ambient temperature; (c) maintaining said adsorbent in contact with said gas until an adsorption-desorption equilibrium is reached so that said gas at said ambient temperature contains a predetermined concentration of said organic compound; and (d) removing a gas sample from said enclosed space containing said predetermined concentration of said organic compound.
Claim 2
Independent Claim
157 words
The method of providing a predetermined concentration of a volatile organic compound in a gas carrier sample, comprising: (a) applying the volatile organic compound free of any other volatile compound to a solid granular adsorbent to partially coat its adsorptive surfaces, the amount of said compound on said adsorbent being less the minimum amount capable of saturating a gas in contact therewith at an ambient temperature, said compound and said adsorbent being chemically non-reactive; (b) introducing said organic compound-containing adsorbent into an enclosed space from which gas samples can be selectively removed, said enclosed space containing a carrier gas in contact with said adsorbent at said ambient temperature; (c) maintaining said adsorbent in contact with said gas until an adsorption-desorption equilibrium is reached so that said gas at said ambient temperature contains a predetermined concentration of said organic compound; and (d) removing a gas sample from said enclosed space containing said predetermined concentration of said organic compound.
Claim 3
Dependent Claim
36 words
The method of claim 1 in which the amount of said organic compound on said adsorbent is less than 10% of the minimum amount capable of saturating a gas in contact therewith at said ambient temperature.
Claim 4
Dependent Claim
41 words
The method of claim 1 in which a plurality of identical gas samples are removed from said enclosed space, the amount of said organic compound removed in each gas sample being less than 0.01% of the amount adsorbed on said adsorbent.
Claim 5
Dependent Claim
12 words
The method of claim 1 in which said adsorbent is silica gel.
Claim 6
Dependent Claim
36 words
The method of claim 1, or claim 2, or claim 3 in which said organic compound is an odor substance and said carrier gas is odorless, whereby said method can be used for dispensing odor samples.
Claim 7
Independent Claim
202 words
The method of providing a predetermined concentration of a volatile organic compound in a gas carrier sample, comprising: (a) applying the volatile organic compound free of any other volatile compound to a solid granular adsorbent to partially coat its adsorptive surfaces, the amount of said organic compound on said adsorbent being limited to less than 10% of the minimum amount capable of saturating a gas in contact therewith at an ambient temperature, said compound and said absorbent being chemically non-reactive; (b) introducing said organic compound-containing adsorbent into an enclosed space from which gas samples can be selectively removed, said enclosed space containing a carrier gas in contact with said adsorbent at said ambient temperature; (c) maintaining said adsorbent in contact with said gas until an adsorption-desorption equilibrium is reached so that said gas at said ambient temperature contains a predetermined concentration of said odor substance; and (d) removing a plurality of gas samples from said enclosed space with said organic compound therein, each of said gas samples containing an amount of said organic compound less than 0.01% of the amount initially adsorbed on said adsorbent, whereby a large number of samples of the same concentration can be removed from said enclosed space.
Claim 8
Independent Claim
202 words
The method of providing a predetermined concentration of a volatile organic compound in a gas carrier sample, comprising: (a) applying the volatile organic compound free of any other volatile compound to a solid granular adsorbent to partially coat its adsorptive surfaces, the amount of said organic compound on said adsorbent being limited to less than 10% of the minimum amount capable of saturating a gas in contact therewith at an ambient temperature, said compound and said absorbent being chemically non-reactive; (b) introducing said organic compound-containing adsorbent into an enclosed space from which gas samples can be selectively removed, said enclosed space containing a carrier gas in contact with said adsorbent at said ambient temperature; (c) maintaining said adsorbent in contact with said gas until an adsorption-desorption equilibrium is reached so that said gas at said ambient temperature contains a predetermined concentration of said odor substance; and (d) removing a plurality of gas samples from said enclosed space with said organic compound therein, each of said gas samples containing an amount of said organic compound less than 0.01% of the amount initially adsorbed on said adsorbent, whereby a large number of samples of the same concentration can be removed from said enclosed space.
Claim 9
Dependent Claim
36 words
The method of claim 6 in which the amount of said organic compound on said adsorbent is less than 1.0% of the minimum amount capable of saturating said gas in contact therewith at said ambient temperature.
Claim 10
Dependent Claim
15 words
The method of claim 6 or claim 7 in which the adsorbent is silica gel.
Claim 11
Dependent Claim
33 words
The method of claim 6 or claim 7 in which said organic compound is an odor substance and said carrier gas is odorless, whereby said method can be used for dispensing odor samples.
Claim 12
Dependent Claim
119 words
An assembly for dispensing gas samples containing a reproducible predetermined concentration of a volatile organic compound, comprising a container with at least one opening to the space enclosed thereby, openable means for closing said opening to seal said container, said space containing a carrier gas in contact with a solid granular adsorbent having a volatile organic compound adsorbed thereon, said organic compound on said adsorbent being free of any other volatile compound and said organic compound and said adsorbent being chemically non-reactive, the amount of said organic compound on said adsorbent being less than 10% of the minimum amount capable of saturating said carrier gas at 25° C., said gas containing a substantially equilibrium concentration of said organic compound.
Claim 13
Dependent Claim
119 words
An assembly for dispensing gas samples containing a reproducible predetermined concentration of a volatile organic compound, comprising a container with at least one opening to the space enclosed thereby, openable means for closing said opening to seal said container, said space containing a carrier gas in contact with a solid granular adsorbent having a volatile organic compound adsorbed thereon, said organic compound on said adsorbent being free of any other volatile compound and said organic compound and said adsorbent being chemically non-reactive, the amount of said organic compound on said adsorbent being less than 10% of the minimum amount capable of saturating said carrier gas at 25° C., said gas containing a substantially equilibrium concentration of said organic compound.
Claim 14
Dependent Claim
27 words
The assembly of claim 10 in which the said gas in said container contains less than 0.01% of the amount of said odor substance on said adsorbent.
Claim 15
Dependent Claim
88 words
The assembly of claim 10 or claim 11 in which said container is in the form of a tube having an inlet at one end for admission of said odorless gas and an outlet at the other end for discharge of gas containing said odor substance, said inlet opening being provided with inlet check valve means, and said outlet opening being provided with outlet check valve means, and said adsorbent being disposed within said tube so that said gas in flowing through said tube passes through said adsorbent.
Claim 16
Dependent Claim
40 words
The assembly of claim 12 in which said outlet opening for said gas sample is connected to a nose adapter to facilitate sniffing of said gas samples, where said assembly can be used with odorous organic compounds as an olfactometer.
Claim 17
Dependent Claim
44 words
The assembly of claim 12 in which said outlet opening for said gas sample is connected to an injector for introducing said sample into a gas analyzer instrument, whereby said assembly can be used to calibrate said instrument for response to said organic compound.
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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) | 1986-06-13 | 1986-12-13 | 1987-06-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-06-13 | 1990-12-13 | 1991-06-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-06-13 | 1994-12-13 | 1995-06-14 | $7700.00 | Window Closed / Lapsed |