US4175207A
Expired / Lapsed
US
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Visual-type hygrometer
Assignee: Individual
•
Filing: 1977-05-09
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Granted: 1979-11-20
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Expires: 1997-05-09
Abstract
Abstract A composition of matter for use in a visual-type instrument which includes a polarizer for a light beam and an analyzer for a light beam, the chemical composition being birefringent at a first relative humidity and nonbirefringent at a second relative humidity.
Inventors
- 👤 Stanley B. Elliott
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 22:57
CPC Classifications
C; C07; C07C; C07C65/00; C07C65/21; C07C65/24; G; G01; G01N; G01N31/00; G01N31/22; G01N31/222; G02; G02B; G02B30/00; G02B30/20; G02B30/22; G02B30/25
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
22 words
The solid, crystalline, hydrated, birefringent tetraalkali salts of 3,3',4,4' benzophenone tetracarboxylic acid consisting of the group of Li, K, Rb, and Cs.
Claim 2
Dependent Claim
22 words
The solid, crystalline, hydrated, birefringent tetraalkali salts of 3,3',4,4' benzophenone tetracarboxylic acid consisting of the group of Li, K, Rb, and Cs.
Claim 3
Dependent Claim
36 words
A mixed crystal of the tetraalkali metal salts of 3,3',4,4' benzophenone tetracarboxylic acid in which at least two different alkali metals are present and function as equivalents to form solid, hydrated, crystals of the non-cubic system.
Claim 4
Dependent Claim
36 words
A mixed crystal of the tetraalkali metal salts of 3,3',4,4' benzophenone tetracarboxylic acid in which at least two different alkali metals are present and function as equivalents to form solid, hydrated, crystals of the non-cubic system.
Claim 5
Dependent Claim
31 words
A mixed crystal of the tetra (lithium, sodium) salts of 3,3',4,4' benzophenone tetracarboxylic acid in which lithium and sodium function as equivalents to form solid, hydrated, crystals of the non-cubic system.
Claim 6
Dependent Claim
31 words
A mixed crystal of the tetra (lithium, sodium) salts of 3,3',4,4' benzophenone tetracarboxylic acid in which lithium and sodium function as equivalents to form solid, hydrated, crystals of the non-cubic system.
Claim 7
Dependent Claim
31 words
A mixed crystal of the tetra (sodium, potassium) salts of 3,3',4,4' benzophenone tetracarboxylic acid in which sodium and potassium function as equivalents to form solid, hydrated, crystals of the non-cubic system.
Claim 8
Dependent Claim
31 words
A mixed crystal of the tetra (sodium, potassium) salts of 3,3',4,4' benzophenone tetracarboxylic acid in which sodium and potassium function as equivalents to form solid, hydrated, crystals of the non-cubic system.
Claim 9
Dependent Claim
31 words
A mixed crystal of the tetra (potassium, rubidium) salts of 3,3',4,4' benzophenone tetracarboxylic acid in which potassium and rubidium function as equivalents to form solid, hydrated, crystals of the non-cubic system.
Claim 10
Dependent Claim
31 words
A mixed crystal of the tetra (potassium, rubidium) salts of 3,3',4,4' benzophenone tetracarboxylic acid in which potassium and rubidium function as equivalents to form solid, hydrated, crystals of the non-cubic system.
Claim 11
Dependent Claim
20 words
The solid, crystalline, hydrated, birefringent alkali metal salts of 3,3',4,4' benzophenone tetracarboxylic acid in which one hydrogen is left unneutralized.
Claim 12
Dependent Claim
20 words
The solid, crystalline, hydrated, birefringent alkali metal salts of 3,3',4,4' benzophenone tetracarboxylic acid in which one hydrogen is left unneutralized.
Claim 13
Dependent Claim
37 words
A mixed crystal of the solid, crystalline, hydrated, birefringent alkali metal salts of 3,3',4,4' benzophenone tetracarboxylic acid in which one hydrogen is left unneutralized and at least two different alkali metals are present and function as equivalents.
Claim 14
Dependent Claim
37 words
A mixed crystal of the solid, crystalline, hydrated, birefringent alkali metal salts of 3,3',4,4' benzophenone tetracarboxylic acid in which one hydrogen is left unneutralized and at least two different alkali metals are present and function as equivalents.
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) | 1982-11-19 | 1983-05-21 | 1983-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-11-19 | 1987-05-21 | 1987-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-11-19 | 1991-05-21 | 1991-11-20 | $7700.00 | Window Closed / Lapsed |