US3771367A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of determining desorption isotherm curve and of scanning hysteresis
Assignee: Quantachrome Corp
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Filing: 1972-05-04
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Granted: 1973-11-13
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Expires: 1992-05-04
Abstract
Abstract As an improvement over the method of our prior U.S. Pat. No. 3,555,912 which uses flowing adsorbate and carrier gases to develop surface measurement data, the within improved method further advances this technique by starting at unity, i.e. pure adsorbate, preparatory to obtaining each data point, to thus reliably permit construction of the desorption isotherm curve. During or subsequent to construction of said desorption curve, having the noted descending character, it is herein contemplated scanning the hysteresis of said curve by measuring at a relative pressure having a contrary relationship to a selected starting point, i.e. an ascending relation. Similarly, data is obtained in the hysteresis of the ascending adsorption isotherm curve by measuring at a relative pressure having a descending, rather than ascending, relation to a starting point.
Inventors
- 👤 S Lowell
- 👤 S Karp
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 02:02
CPC Classifications
G; G01; G01N; G01N15/00; G01N15/08; G01N15/088; G01N15/0893
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
229 words
An improved method of using selected adsorbates and inert gas mixtures to determine the desorption isotherm curve of a test powder surface preparatory to determining characteristics of said surface, said method including a first step of establishing a reference starting point by passing only 100 percent pure adsorbate in adsorbing relation to said test powder surface until conclusion of the adsorption of said adsorbate to said surface, a second step of passing a selected mixture of less than 100 percent adsorbate and a remaining percentage of an inert gas in adsorbing relation to said test powder surface until conclusion of the adsorption of said adsorbate to said surface, a third step of determining a data point for said isotherm curve as a function of the amount of adsorbate desorbed as a consequence of said second step, a succeeding step of sequentially repeating said first step and second step hereof, the atter with a selected mixture of a lesser percentage of adsorbate and greater percentage of inert gas than previously used, and a succeeding step after each said sequential repeat of said first and second steps of repeating said third step hereof to determine an additional data point for said isotherm curve, whereby desorption isotherm curve date points are determined which each are of a descending character relative to said established starting point determined using only said 100 percent adsorbate.
Claim 2
Dependent Claim
229 words
An improved method of using selected adsorbates and inert gas mixtures to determine the desorption isotherm curve of a test powder surface preparatory to determining characteristics of said surface, said method including a first step of establishing a reference starting point by passing only 100 percent pure adsorbate in adsorbing relation to said test powder surface until conclusion of the adsorption of said adsorbate to said surface, a second step of passing a selected mixture of less than 100 percent adsorbate and a remaining percentage of an inert gas in adsorbing relation to said test powder surface until conclusion of the adsorption of said adsorbate to said surface, a third step of determining a data point for said isotherm curve as a function of the amount of adsorbate desorbed as a consequence of said second step, a succeeding step of sequentially repeating said first step and second step hereof, the atter with a selected mixture of a lesser percentage of adsorbate and greater percentage of inert gas than previously used, and a succeeding step after each said sequential repeat of said first and second steps of repeating said third step hereof to determine an additional data point for said isotherm curve, whereby desorption isotherm curve date points are determined which each are of a descending character relative to said established starting point determined using only said 100 percent adsorbate.
Claim 3
Dependent Claim
83 words
A method of scanning the hysteresis region of said desorption isotherm curve of claim 1 comprising the steps of passing a selected mixture of an adsorbate gas and an inert gas having a corresponding relative pressure in an ascending relation to a prior-used mixture thereof in adsorbing relation to said test powder surface until conclusion of the adsorption of said adsorbate to said surface, and measuring the amount of adsorbate desorbed from said test powder surface to obtain said hysteresis region data point.
References Cited (Backward Citations)
US3211007A
Cited
US3555912A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-12 | 1977-05-14 | 1977-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-12 | 1981-05-14 | 1981-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-12 | 1985-05-14 | 1985-11-13 | $7700.00 | Window Closed / Lapsed |