US3538008A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cleaning of sewers and drains
Assignee: Madison Chemical Co Inc
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Filing: 1968-09-13
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Granted: 1970-11-03
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Expires: 1988-09-13
Abstract
Abstract 1,234,152. Sewer cleaning compositions. MADISON CHEMICAL CORP. 15 Jan., 1969, No. 2307/69. Heading C5D. A sewer-cleaning composition in flowable granular form comprises at least 40% wt. of one or more strong mineral acids and at least 5% wt. of a finely divided silica aerogel, especially a pyrogenic silica having a particle size below 1 micron. The acids may be hydrochloric, nitric or phosphoric, but sulphuric acid is preferred. Optional ingredients are (a) ampholytic detergents such as sodium or disodium salt of N-lauryl beta iminodipropionic acid, (b) corrosion inhibitors e.g. alkali metal chromates or dichromates, dipentylamine or decamethyleneimine and (c) fillers e.g. silica.
Inventors
- 👤 Selwyn J Ancel
- 👤 Seymour Leavitt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 06:27
CPC Classifications
B; B08; B08B; B08B9/00; B08B9/02; B08B9/027; B08B9/04; B08B9/053; B08B9/057; C; C11; C11D; C11D7/00; C11D7/02; C11D7/04; C11D7/08; C11D7/20; E; E03; E03F; E03F9/00
Claims Analysis
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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) | 1973-11-02 | 1974-05-04 | 1974-11-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-11-02 | 1978-05-04 | 1978-11-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-11-02 | 1982-05-04 | 1982-11-03 | $7700.00 | Window Closed / Lapsed |