US3615246A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Steady state etching system
Assignee: International Business Machines Corp
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Filing: 1969-10-08
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Granted: 1971-10-26
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Expires: 1989-10-08
Abstract
Abstract A steady state system for the etching of printed circuit boards is provided. A metal is removed from an etchant at the rate in which it is dissolved into the etchant and etching reagent consumed during the etching process is replaced at an equivalent rate. Also provided is an improved crystallization tower which is used to continuously remove the dissolved metal. The tower is provided with a series of adjustable baffles to vary the inner diameter of the tower to control crystal size throughout the column. Additionally, there is included a crystal ejection chamber from which precipitated crystals are ejected by a centrifugal force.
Inventors
- 👤 Robert T Lindstrom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 11:37
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/46; B; B01; B01D; B01D9/00; B01D9/0004; B01D9/0013; B01D9/0036; B01D9/0059; B01D9/0063; B01F; B01F21/00; B01F21/20; B01F21/30
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
57 words
The continuous crystallization tower of claim 1 further including a return input means at the base of said crystal ejection chamber, said return input means communicating with the inner area of said first cylindrical portion of said container to permit the return inflow of mother liquor thereto, said mother liquor having been discharged with the ejected crystals.
Claim 2
Dependent Claim
30 words
The crystallization tower of claim 1 further including crystal collection means communicative with said crystal ejection chamber comprising a crystal collection chamber having means to entrap the crystals entering therein.
Claim 3
Dependent Claim
38 words
The continuous crystallization tower of claim 3 further including heat exchange means to cool mother liquor being introduced into said crystal ejection chamber just prior to its entrance into said chamber thereby creating metastability in the mother liquor.
Claim 4
Dependent Claim
70 words
The continuous crystallization tower of claim 4 further including manual bypass means comprising pair of lateral openings in a sidewall of said first cylindrical portion, conduit means connecting said openings, and valve means to control the flow of mother liquor through said conduit means, said manual bypass means operating to prevent the packing of crystals in the lower sections of the tower, and to provide additional product crystal size control.
Claim 5
Dependent Claim
36 words
The continuous crystallization tower of claim 9 further including means to introduce seed crystals into the top of said tower, said seed crystals inducing crystal growth to occur within the metastable mother liquor in said tower.
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) | 1974-10-25 | 1975-04-26 | 1975-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-25 | 1979-04-26 | 1979-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-25 | 1983-04-26 | 1983-10-26 | $7700.00 | Window Closed / Lapsed |