Patent US4256856A successfully refreshed from Google Patents.
US4256856A
Expired / Lapsed
US
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Components of uranium enrichment plant
Assignee: Japan Atomic Energy Agency
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Filing: 1977-08-15
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Granted: 1981-03-17
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Expires: 1997-08-15
Abstract
Abstract A cross-linked product of ethylene-hexafluoropropylene copolymer is a good elastic material and has excellent resistance to attack by uranium hexafluoride even at a high temperature. Components made of said copolymer exhibit surprisingly long life, when used in a uranium enrichment plant.
Inventors
- 👤 Masayuki Ito
- 👤 Giro Okamoto
- 👤 Sueo Machi
- 👤 Kenzo Shirayama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 19:28
CPC Classifications
B; B01; B01D; B01D59/00; B01D59/20; C; C08; C08F; C08F214/00; C08F214/18; C08F214/28; C08L; C08L23/00; C08L23/02; C08L23/04; C08L23/08; C08L23/0846; C08L23/0892
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
65 words
In a uranium enrichment plant containing a component of a device, the improvement wherein said component is formed of a cross-linked elastic copolymer of ethylene and hexafluoropropylene prepared by cross-linking a copolymer of ethylene and hexafluoropropylene containing 10 to 50% by mole of hexafluoropropylene and having a melt index before cross-linking in the range of 1 to 300 determined at a load of 2.16 kg.
Claim 2
Dependent Claim
65 words
In a uranium enrichment plant containing a component of a device, the improvement wherein said component is formed of a cross-linked elastic copolymer of ethylene and hexafluoropropylene prepared by cross-linking a copolymer of ethylene and hexafluoropropylene containing 10 to 50% by mole of hexafluoropropylene and having a melt index before cross-linking in the range of 1 to 300 determined at a load of 2.16 kg.
Claim 3
Dependent Claim
75 words
A device as defined in claim 1, wherein the cross-linked copolymer is prepared by adding 0.1 to 10 parts by weight of an organic peroxide to 100 parts by weight of a copolymer of ethylene and hexafluoropropylene containing 10 to 50% by mole of hexafluoropropylene and having a melt index in the range of 1 to 300 measured at a load of 2.16 kg, followed by heating the resulting copolymer composition to bring about cross-linking.
Claim 4
Dependent Claim
59 words
A device as defined in claim 2, wherein said heating step is carried out in two stages comprising the first stage which is carried out at a temperature in the range of 140°-180° C. for 10-50 minutes and the second stage which is carried out at a temperature in the range of 190°-220° C. for 0.5 to 24 hours.
Claim 5
Dependent Claim
52 words
A device as defined in claim 1, wherein the cross-linked copolymer is prepared by subjecting a copolymer of ethylene and hexafluoropropylene containing 10 to 50% by mole of hexafluoropropylene and having a melt index in the range of 1 to 300 measured at a load of 2.16 kg to an ionizing radiation.
Claim 6
Dependent Claim
35 words
A device as defined in claim 4, wherein the ionizing radiation treatment is carried out by making use of a radiation source selected from the group consisting of gamma-rays, X-rays, beta-rays, alpha-rays and electron beams.
Claim 7
Dependent Claim
23 words
A device as defined in claim 4, wherein the ionizing radiation source is selected from the group consisting of gamma-rays and electron beams.
Claim 8
Dependent Claim
36 words
A device as defined in claim 6, wherein the irradiation is carried out at a dose rate in the range of 10 3 -10 10 rads/hr for a total dose in the range of 1-50 Mrads.
Claim 9
Dependent Claim
36 words
A device as defined in claim 7, wherein the irradiation is carried out at a dose rate in the range of 10 4 -10 9 rads/hr for a total dose in the range of 5-30 Mrads.
Claim 10
Dependent Claim
15 words
A device as defined in claim 1, wherein said component is a packing or sealant.
Claim 11
Dependent Claim
15 words
A device as defined in claim 2, wherein said component is a packing or sealant.
Claim 12
Dependent Claim
15 words
A device as defined in claim 4, wherein said component is a packing or sealant.
Claim 13
Dependent Claim
14 words
A device as set forth in claim 1, wherein said component is a lining.
Claim 14
Dependent Claim
14 words
A device as set forth in claim 2, wherein said component is a lining.
Claim 15
Dependent Claim
14 words
A device as set forth in claim 4, wherein said component is a lining.
Claim 16
Dependent Claim
15 words
A device as set forth in claim 1, wherein said component is a shock-absorbing member.
Claim 17
Dependent Claim
15 words
A device as set forth in claim 2, wherein said component is a shock-absorbing member.
Claim 18
Dependent Claim
15 words
A device as set forth in claim 4, wherein said component is a shock-absorbing member.
Claim 19
Dependent Claim
53 words
A component of an uranium enrichment plant formed of a cross-linked elastic copolymer of ethylene and hexafluoropropylene prepared by cross-linking a copolymer of ethylene and hexafluoropropylene containing 10 to 50 mole percent of hexafluoropropylene and having a melt index before cross-linking in the range of 1-300 determined at a load of 2.16 kg.
Claim 20
Dependent Claim
53 words
A component of an uranium enrichment plant formed of a cross-linked elastic copolymer of ethylene and hexafluoropropylene prepared by cross-linking a copolymer of ethylene and hexafluoropropylene containing 10 to 50 mole percent of hexafluoropropylene and having a melt index before cross-linking in the range of 1-300 determined at a load of 2.16 kg.
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) | 1984-03-16 | 1984-09-15 | 1985-03-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-16 | 1988-09-15 | 1989-03-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-16 | 1992-09-15 | 1993-03-17 | $7700.00 | Window Closed / Lapsed |