Patent US4977749A successfully refreshed from Google Patents.
US4977749A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus and method for purification of gases used in exciplex (excimer) lasers
Assignee: Individual
•
Filing: 1989-04-25
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Granted: 1990-12-18
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Expires: 2009-04-25
Abstract
Abstract A system and method for the purification of laser gases having impurities therein. The pressure on the liquid nitrogen in a Dewar vessel controls the boiling point of the liquid nitrogen. The laser gas to be purified flows into heat exchange relationship with the liquid nitrogen at a temperature above the liquification temperature of the laser gas but below the liquification temperature of the impurities. The impurities are precipitated and removed and the laser gas recycled for further use.
Inventors
- 👤 Jeffrey P. Sercel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 15:55
CPC Classifications
B; B01; B01D; B01D8/00
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
91 words
An apparatus for the purification of laser gases having impurities which comprises: a Dewar vessel adapted to hold liquid nitrogen therein; means to control the pressure of the nitrogen in the vessel and thereby the boiling point of the liquid nitrogen; means to flow the laser gas to be purified into heat exchange relationship with the liquid nitrogen at a temperature above the liquification temperature of the gas and below the liquification temperature of the impurities to freeze and to precipitate the impurities; and means to remove the impurities so precipitated.
Claim 2
Independent Claim
91 words
An apparatus for the purification of laser gases having impurities which comprises: a Dewar vessel adapted to hold liquid nitrogen therein; means to control the pressure of the nitrogen in the vessel and thereby the boiling point of the liquid nitrogen; means to flow the laser gas to be purified into heat exchange relationship with the liquid nitrogen at a temperature above the liquification temperature of the gas and below the liquification temperature of the impurities to freeze and to precipitate the impurities; and means to remove the impurities so precipitated.
Claim 3
Dependent Claim
15 words
The apparatus of claim 1 wherein the means to remove the impurities comprises a filter.
Claim 4
Dependent Claim
35 words
The apparatus of claim 1 wherein the means to introduce the gas and remove the gas comprises an outlet and an inlet received in the Dewar, which inlet and outlet extend into the liquid nitrogen.
Claim 5
Independent Claim
75 words
A method for the purification of laser gases having impurities which includes: controlling the pressure of liquid nitrogen in a vessel and thereby the boiling point of the liquid nitrogen; flowing the laser gas to be purified into heat exchange relationship with the liquid nitrogen at a temperature above the liquification temperature of the gas and below the liquification temperature of the impurities; freezing the impurities; precipitating the impurities; and removing the impurities so formed.
Claim 6
Independent Claim
75 words
A method for the purification of laser gases having impurities which includes: controlling the pressure of liquid nitrogen in a vessel and thereby the boiling point of the liquid nitrogen; flowing the laser gas to be purified into heat exchange relationship with the liquid nitrogen at a temperature above the liquification temperature of the gas and below the liquification temperature of the impurities; freezing the impurities; precipitating the impurities; and removing the impurities so formed.
Claim 7
Dependent Claim
10 words
The method of claim 4 wherein the impurities are halogens.
Claim 8
Dependent Claim
12 words
The method of claim 5 wherein the halogens are fluorine and chlorine.
Claim 9
Dependent Claim
23 words
The method of claim 4 wherein the laser gases are selected from the group consisting of argon fluoride, krypton fluoride and xenon chloride.
Claim 10
Dependent Claim
12 words
The method of claim 4 wherein the laser gas is krypton fluoride.
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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) | 1993-12-17 | 1994-06-18 | 1994-12-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-12-17 | 1998-06-18 | 1998-12-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-12-17 | 2002-06-18 | 2002-12-18 | $7700.00 | Window Closed / Lapsed |