Patent US3837809A successfully refreshed from Google Patents.
US3837809A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sterilizing procedures
Assignee: Individual
•
Filing: 1972-11-29
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Granted: 1974-09-24
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Expires: 1992-11-29
Abstract
Abstract Indicator means for showing that a surgical material or appliance has been sterilized by steam and formaldehyde vapour, the indicator means comprising a carrier for a sulphite to react with the formaldehyde to produce an alkali, and an indicator for the alkali having a change point on the alkaline side of neutrality.
Inventors
- 👤 A Chapman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:43
CPC Classifications
G; G01; G01N; G01N31/00; G01N31/22; G01N31/221
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
38 words
Indicator means as in claim 1, wherein the carrier having the sulphite and indicator deposited thereon is enclosed in a cover having sufficient permeability and thickness to delay contact by the steam and formaldehyde vapour with the carrier.
Claim 2
Dependent Claim
13 words
Indicator means as in claim 2, wherein the cover is formed of polyethylene.
Claim 3
Dependent Claim
23 words
Indicator means as in claim 1, wherein a sufficient proportion of a bisulphite is added to the sulphite to delay the color change.
Claim 4
Dependent Claim
14 words
Indicator means as in claim 4, wherein the bisulphite is sodium or potassium metabisulphite.
Claim 5
Dependent Claim
12 words
Indicator means as in claim 1, wherein the sulphite is sodium sulphite.
Claim 6
Dependent Claim
11 words
Indicator means as in claim 6, wherein the indicator is phenolphthalein.
Claim 7
Dependent Claim
20 words
Indicator means as in claim 7, wherein the carrier is a piece of paper or fabric of a porous nature.
References Cited (Backward Citations)
US3232710A
Cited
US3288718A
Cited
US3360339A
Cited
US3409405A
Cited
US3523011A
Cited
US3684737A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-23 | 1978-03-25 | 1978-09-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-23 | 1982-03-25 | 1982-09-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-23 | 1986-03-25 | 1986-09-24 | $7700.00 | Window Closed / Lapsed |