US3850602A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Salt vapor atmosphere treatment of quartz crystal granules
Assignee: Heraeus Schott Quarzschmelze GmbH
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Filing: 1972-12-18
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Granted: 1974-11-26
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Expires: 1992-12-18
Abstract
Abstract Bubble-free and OH-free quartz glass is made from granular quartz crystal by doping quartz crystal granules with a salt whose cation is selected from the group of lithium, sodium, potassium, magnesium, calcium, strontium and silver, and having, at temperatures ranging from 800* to 1,700*C., a vapor pressure of at least 5 mm Hg, preferably of more than 100 mm Hg, or with a mixture of such salts, in a quantity corresponding at least to the OH content of the quartz crystal granules, stirring and doped quartz crystal granules for a period of at least 30 seconds in a reaction chamber heated to a temperature ranging from 800* to 1,700*C. and having an atmosphere enriched with a salt vapor, flooding the stirred quartz crystal granules with a water vaporfree gas at a temperature ranging from 800* to 1,700*C., and melting the gas-flooded quartz crystal granules in a water-vaporfree atmosphere in a known melting furnace.
Inventors
- 👤 R Bruning
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 07:20
CPC Classifications
C; C03; C03C; C03C3/00; C03C3/04; C03C3/06; C03C1/00; C03C1/02; C03C2201/00; C03C2201/06; C03C2201/30; C03C2201/50; C03C2201/54; C03C2203/00; C03C2203/10; Y; Y10; Y10S; Y10S65/00; Y10S65/90
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
171 words
PROCESS FOR THE MANUFACTURE OF SUBSTANTIALLY BUBBLE-FREE AND OH-FREE AMORPHOUS QUARTZ GLASS FROM QUARTZ CRYSTAL GRANULES HAVING A PRE-DETERMINED OH CONTENT WHICH COMPRISES A. DOPING SAID QUARTZ CRYSTAL GRANULES WITH A SALT OR MIXTURE OF SALTS WHOSE CATION IS SELECTED FROM THE GROUP OF LITHIUM SODUUM POTASSIUM, MAGNESIUM, CALCIUM, STRONTIUM AND SILVER EACH SALT HAVING AT TEMPERATURES IN THE RANGE FROM 800* TO 1,700*C A VAPOR PRESSURE OF AT LEAST 5 MM HG, IN A QUANTITY CORRESPONDING AT LEAST TO THE -OH CONTENT OF SAID QUARTZ CRYSTAL GRANULES, B. STIRRING THE DOPED QUARTZ CRYSTAL GRANULES FOR A PERIOD OF AT LEAST 30 SECONDS IN A REACTION CHAMBER HEATED TO A TEMPERATURE RANGING FROM 800 TO 1,700*C HAVING AN ATMOSPHERE ENRICHED WITH SALT VAPOR, THEREBY CAUSING A PARTIAL PRESSURE TO FORM CORRESPONDING TO THE VAPOR PRESSURE OF SAID SALT, C. FLOODING THE TUMBLED QUARTZ CRYSTAL GRANULES WITH A WATER VAPOR-FREE GAS AT A TEMPERAURE RANGING FROM 800* TO 1,700*C., AND D. MELTING THE GAS-FLOODED QUARTZ CRYSTAL GRANULES UNDER A WATER VAPOR-FREE ATMOSPHERE.
Claim 2
Dependent Claim
171 words
PROCESS FOR THE MANUFACTURE OF SUBSTANTIALLY BUBBLE-FREE AND OH-FREE AMORPHOUS QUARTZ GLASS FROM QUARTZ CRYSTAL GRANULES HAVING A PRE-DETERMINED OH CONTENT WHICH COMPRISES A. DOPING SAID QUARTZ CRYSTAL GRANULES WITH A SALT OR MIXTURE OF SALTS WHOSE CATION IS SELECTED FROM THE GROUP OF LITHIUM SODUUM POTASSIUM, MAGNESIUM, CALCIUM, STRONTIUM AND SILVER EACH SALT HAVING AT TEMPERATURES IN THE RANGE FROM 800* TO 1,700*C A VAPOR PRESSURE OF AT LEAST 5 MM HG, IN A QUANTITY CORRESPONDING AT LEAST TO THE -OH CONTENT OF SAID QUARTZ CRYSTAL GRANULES, B. STIRRING THE DOPED QUARTZ CRYSTAL GRANULES FOR A PERIOD OF AT LEAST 30 SECONDS IN A REACTION CHAMBER HEATED TO A TEMPERATURE RANGING FROM 800 TO 1,700*C HAVING AN ATMOSPHERE ENRICHED WITH SALT VAPOR, THEREBY CAUSING A PARTIAL PRESSURE TO FORM CORRESPONDING TO THE VAPOR PRESSURE OF SAID SALT, C. FLOODING THE TUMBLED QUARTZ CRYSTAL GRANULES WITH A WATER VAPOR-FREE GAS AT A TEMPERAURE RANGING FROM 800* TO 1,700*C., AND D. MELTING THE GAS-FLOODED QUARTZ CRYSTAL GRANULES UNDER A WATER VAPOR-FREE ATMOSPHERE.
Claim 3
Dependent Claim
26 words
Process of claim 1 wherein the quartz crystal granules are mixed with the salt or salt mixture prior to introduction into the reaction chamber or therein.
Claim 4
Dependent Claim
33 words
Process of claim 1 wherein a salt solution is added to the entire batch of quartz crystal granules, dried at a temperature of less than 500*C., and then transferred into thE reaction chamber.
Claim 5
Dependent Claim
44 words
Process of claim 1 wherein a portion of the total batch of quartz crystal granules is treated with a more highly concentrated salt solution, dried, mixed with the remainder of the batch of untreated quartz crystal granules, and then introduced into the reaction chamber.
Claim 6
Dependent Claim
61 words
Process of claim 1 wherein the quartz crystal granules are mixed with a salt selected from the group of sodium fluoride, sodium bromide, sodium nitrate, lithium chloride, potassium chloride, magnesium chloride, calcium chloride, strontium chloride, silver nitrate, and mixtures of two or more of the foregoing salts, or are treated with a salt solution of one or more of said salts.
Claim 7
Dependent Claim
27 words
Process of claim 1 wherein the tumbling of the doped quartz crystal granules and the gas flooding are carried out at temperatures ranging from 900* to 1,400*C.
Claim 8
Dependent Claim
18 words
Process of claim 1 wherein gas flooding of the tumbled quartz crystal granules is carried out in counterflow.
Claim 9
Dependent Claim
14 words
Process of claim 1 wherein oxygen or nitrogen is used for the gas flooding.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-11-25 | 1978-05-27 | 1978-11-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-25 | 1982-05-27 | 1982-11-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-25 | 1986-05-27 | 1986-11-26 | $7700.00 | Window Closed / Lapsed |