US3768974A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Disposable colorimetric indicator device for measuring the concentration of chlorine in water
Assignee: Pymah Corp
•
Filing: 1971-03-22
•
Granted: 1973-10-30
•
Expires: 1991-03-22
Abstract
Abstract A disposable plastic syringe contains a measured quantity of a water-soluble colorimetric reagent composition proportioned to the volume of water sample which may be drawn into the syringe. The color produced in the water sample is compared to a chart standard which indicates the concentration of chlorine in the water sample. The measured quantity of the reagent composition is preferably applied as a dried printed spot applied to an inside surface of the syringe device.
Inventors
- 👤 L Storm
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 16:52
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/18; G01N33/182; G01N31/00; G01N31/22; Y; Y10; Y10T; Y10T436/00; Y10T436/19; Y10T436/193333
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
16 words
The device defined in claim 1, in which the composition also contains a pH buffering salt.
Claim 2
Dependent Claim
33 words
The device defined in claim 1, in which the composition also contains potassium aluminum sulfate in an amount to control the pH of the water sample to a range of 3.8 to 4.2.
Claim 3
Dependent Claim
21 words
The device defined in claim 1 in which the composition also contains as a color brightener a water soluble bromide salt.
Claim 4
Dependent Claim
64 words
A water soluble composition for colorimetrically measuring the concentration of chlorine in a sample of water, comprising Acid fuchsin - 0.8 to 80 parts by weight; ortho tolidine dihydrochloride - 4 to 400 parts by weight; potassium bromide - 375 to 1,500 parts by weight; aluminum potassium sulfate 12H2O - 500 to 2,000 parts by weight and a water soluble binder in effective proportion.
Claim 5
Dependent Claim
17 words
The composition defined in claim 5 in which said added binder is polyvinyl pyrrolidone in effective proportion.
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) | 1976-10-29 | 1977-04-30 | 1977-10-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-29 | 1981-04-30 | 1981-10-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-29 | 1985-04-30 | 1985-10-30 | $7700.00 | Window Closed / Lapsed |