US3733994A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for washing of photographic material
Assignee: STEK CORP
•
Filing: 1970-09-16
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Granted: 1973-05-22
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Expires: 1990-09-16
Abstract
Abstract An apparatus for controlling the contamination level of photo wash water supporting an environment for ionic substitution of simple thiosulfate salts in the water with complex argento thiosulfates on the photographic emulsion surface. A water purifier is placed in closed loop with the wash tank to control the level of contamination.
Inventors
- 👤 C Armstrong
- 👤 A Cronig
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:34
CPC Classifications
G; G03; G03C; G03C5/00; G03C5/26; G03C5/29; G03C5/31; G03D; G03D3/00; G03D3/02; G03D3/06; G03D3/065
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
77 words
Apparatus for washing photographic material comprising: a bath for containing wash water through which the material passes; means for removing the wash water which is contaminated by the material from the bath; means for lowering the contamination level of the removed water; means for introducing partially decontaminated water into the wash bath; and, means for maintaining the level of contamination in the wash water within a range of from about 80 to about 10,000 parts per million.
Claim 2
Dependent Claim
77 words
Apparatus for washing photographic material comprising: a bath for containing wash water through which the material passes; means for removing the wash water which is contaminated by the material from the bath; means for lowering the contamination level of the removed water; means for introducing partially decontaminated water into the wash bath; and, means for maintaining the level of contamination in the wash water within a range of from about 80 to about 10,000 parts per million.
Claim 3
Dependent Claim
40 words
An apparatus of claim 1 further including means for shunting a quantity of the contaminated water around the contamination lowering means; and, means for mixing quantities of the decontaminated water with the shunted water prior to introduction into the bath.
Claim 4
Dependent Claim
40 words
An apparatus of claim 2 wherein said mixing means includes a contamination sensor and a contamination control operatively connected to said sensor whereby the level of contamination of the wash water in the bath is kept at a constant level.
Claim 5
Dependent Claim
17 words
An apparatus of claim 3 wherein the means for lowering the contamination level comprises a flash evaporator.
Claim 6
Dependent Claim
22 words
An apparatus of claim 1 wherein the pH of the wash water is within the range from about 4.7 to about 4.9.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-05-21 | 1976-11-20 | 1977-05-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-21 | 1980-11-20 | 1981-05-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-21 | 1984-11-20 | 1985-05-22 | $7700.00 | Window Closed / Lapsed |