Patent US4156598A successfully refreshed from Google Patents.
US4156598A
Expired / Lapsed
US
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Purification of nitrogen trifluoride atmospheres
Assignee: Air Products and Chemicals Inc
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Filing: 1978-06-08
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Granted: 1979-05-29
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Expires: 1998-06-08
Abstract
Abstract {PG,1 This invention relates to an improvement in a process for purifying nitrogen trifluoride atmospheres generally contaminated with nitrous oxide, water, and dinitrogen difluoride. The improvement for extending adsorber life resides in reducing the dinitrogen difluoride content in the atmosphere to less than 0.03% by volume prior to passing the atmosphere through the adsorber.
Inventors
- 👤 Andrew J. Woytek
- 👤 John T. Lileck
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 09:37
CPC Classifications
C; C01; C01B; C01B21/00; C01B21/082; C01B21/083; C01B21/0832; B; B01; B01D; B01D53/00; B01D53/02; Y; Y02; Y02C; Y02C20/00; Y02C20/10; Y02P; Y02P20/00; Y02P20/151; Y10; Y10S; Y10S95/00; Y10S95/90; Y10S95/902
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
72 words
In a process for removing nitrous oxide from a nitrogen trifluoride atmosphere contaminated with dinitrogen difluoride, which comprises passing said atmosphere through an adsorption zone containing a synthetic zeolite adsorbent, the improvement for treating atmospheres having a dinitrogen difluoride content greater than 0.05% by volume and extending the adsorber life which comprises: reducing the dinitrogen difluoride content to less than 0.03% by volume prior to contacting said atmosphere with said zeolite adsorbent.
Claim 2
Dependent Claim
72 words
In a process for removing nitrous oxide from a nitrogen trifluoride atmosphere contaminated with dinitrogen difluoride, which comprises passing said atmosphere through an adsorption zone containing a synthetic zeolite adsorbent, the improvement for treating atmospheres having a dinitrogen difluoride content greater than 0.05% by volume and extending the adsorber life which comprises: reducing the dinitrogen difluoride content to less than 0.03% by volume prior to contacting said atmosphere with said zeolite adsorbent.
Claim 3
Dependent Claim
20 words
The process of claim 1 wherein the initial dinitrogen difluoride content in said atmosphere is from about 0.05-3% by volume.
Claim 4
Dependent Claim
21 words
The process of claim 2 wherein said atmosphere is contaminated with water and the zeolite is capable of removing said water.
Claim 5
Dependent Claim
30 words
The process of claim 3 wherein the dinitrogen difluoride content in said atmosphere is reduced to less than 0.01% by volume prior to contacting the atmosphere with said zeolite adsorbent.
Claim 6
Dependent Claim
16 words
The process of claim 1 wherein said atmosphere contains from about 5-50% nitrogen trifluoride by volume.
Claim 7
Dependent Claim
33 words
The process of claims 2, 3, 4 or 5 wherein the ratio of nitrogen trifluoride to dinitrogen difluoride in said atmosphere is greater than 5,000 prior to passing said atmosphere through said adsorber.
Claim 8
Dependent Claim
24 words
The process of claim 1 wherein said synthetic zeolite adsorbent is selected from the group consisting of an alkali and alkaline earth metal alumino-silicate.
Claim 9
Dependent Claim
11 words
The process of claim 7 wherein said alkali metal is sodium.
Claim 10
Dependent Claim
12 words
The process of claim 7 wherein said alkaline earth metal is calcium.
Claim 11
Dependent Claim
21 words
The process of claims 8 or 9 wherein said zeolite adsorbent has a crystal structure of the X or A type.
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) | 1982-05-28 | 1982-11-27 | 1983-05-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-05-28 | 1986-11-27 | 1987-05-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-05-28 | 1990-11-27 | 1991-05-29 | $7700.00 | Window Closed / Lapsed |