US4743718A
Expired / Lapsed
US
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Electrical contacts for vacuum interrupter devices
Assignee: Westinghouse Electric Corp
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Filing: 1987-07-13
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Granted: 1988-05-10
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Expires: 2007-07-13
Abstract
Abstract A vacuum interrupter device 11 with contacts 21 and 27 formed from a mixture of copper, chromium, bismuth, and at least about 0.5 weight percent of chromic oxide. The mixture can additionally include small amounts of silver, iron and titanium. The chromic oxide hinders copper grain growth, binds bismuth in the matrix, and increases vacuum dielectric strength in the vacuum interrupter.
Inventors
- 👤 Vincent J. Santilli
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 05:49
CPC Classifications
H; H01; H01H; H01H33/00; H01H33/60; H01H33/66; H01H1/00; H01H1/02; H01H1/0203; H01H1/0206
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
42 words
A porous briquette, useful as a vacuum interrupter contact after sintering, containing a powder mixture comprising 50 to 75 weight percent copper, 15 to 30 weight percent chromium, 2.5 to 15 weight percent bismuth and 0.5 to 7.5 weight percent chromic oxide.
Claim 2
Dependent Claim
42 words
A porous briquette, useful as a vacuum interrupter contact after sintering, containing a powder mixture comprising 50 to 75 weight percent copper, 15 to 30 weight percent chromium, 2.5 to 15 weight percent bismuth and 0.5 to 7.5 weight percent chromic oxide.
Claim 3
Dependent Claim
21 words
The briquette according to claim 1, where the chromic oxide constitutes from 1 to 3 percent by weight of the mixture.
Claim 4
Dependent Claim
33 words
The briquette according to claim 1, where the mixture also includes at least one metal selected from the group consisting of silver, iron, and titanium in an amount greater than an impurity level.
Claim 5
Dependent Claim
64 words
A dense vacuum interrupter contact obtained by sintering, in an atmosphere partly oxidative to chromium and reductive to copper and bismuth, a powder mixture comprising 50 to 75 weight percent copper, 15 to 30 weight percent chromium, 2.5 to 15 weight percent bismuth, and 0.5 to 7.5 weight percent chromic oxide, said interrupter characterized by high current interruption and a high dispersion of bismuth.
Claim 6
Dependent Claim
64 words
A dense vacuum interrupter contact obtained by sintering, in an atmosphere partly oxidative to chromium and reductive to copper and bismuth, a powder mixture comprising 50 to 75 weight percent copper, 15 to 30 weight percent chromium, 2.5 to 15 weight percent bismuth, and 0.5 to 7.5 weight percent chromic oxide, said interrupter characterized by high current interruption and a high dispersion of bismuth.
Claim 7
Dependent Claim
23 words
The vacuum interrupter contact according to claim 4, wherein the chromic oxide constitutes from 1 to 3 percent by weight of the mixture.
Claim 8
Dependent Claim
35 words
The vacuum interrupter contact according to claim 4, wherein the mixture also includes at least one metal selected from the group consisting of silver, iron and titanium in an amount greater than an impurity level.
Claim 9
Dependent Claim
57 words
A dense vacuum interrupter contact which exhibits high current interruption, obtained by sintering a mixture comprising copper, chromium and bismuth, the improvement characterized in that the mixture is sintered in an atmosphere partly oxidative to chromium and reductive to copper and bismuth, and also contains from 0.5 to 7.5 weight percent of Cr 2 O 3 .
Claim 10
Dependent Claim
57 words
A dense vacuum interrupter contact which exhibits high current interruption, obtained by sintering a mixture comprising copper, chromium and bismuth, the improvement characterized in that the mixture is sintered in an atmosphere partly oxidative to chromium and reductive to copper and bismuth, and also contains from 0.5 to 7.5 weight percent of Cr 2 O 3 .
Claim 11
Dependent Claim
25 words
The vacuum interrupter contact according to claim 7, wherein the Cr 2 O 3 constitutes from 1 to 3 percent by weight of the mixture.
Claim 12
Dependent Claim
76 words
A dense, sintered vacuum interrupter contact comprising 2.5 to 15 weight percent bismuth finely dispersed among 50 to 75 weight percent copper grains having a particle size below 300 microns, with the remainder of the contact containing chromium, and oxides of chromium selected from the group consisting of Cr 2 O 3 , CrO 3 , and their mixtures, where the oxides of chromium surround the copper, bismuth and chromium, in a binding, uniformly distributed network.
Claim 13
Dependent Claim
76 words
A dense, sintered vacuum interrupter contact comprising 2.5 to 15 weight percent bismuth finely dispersed among 50 to 75 weight percent copper grains having a particle size below 300 microns, with the remainder of the contact containing chromium, and oxides of chromium selected from the group consisting of Cr 2 O 3 , CrO 3 , and their mixtures, where the oxides of chromium surround the copper, bismuth and chromium, in a binding, uniformly distributed network.
Claim 14
Dependent Claim
82 words
A vacuum interrupter device 11, comprising a pair of dense, sintered contacts 21 and 27 movable into either a closed circuit contact with each other or an open circuit, spaced relation relative to each other, said contacts obtained by sintering in an atmosphere partly oxidative to chromium and reductive to copper and bismuth, a mixture comprising 50 to 75 weight percent coopper, 15 to 30 weight percent chromium, 2.5 to 15 weight percent bismuth, and 0.5 to 7.5 weight percent chromic oxide.
Claim 15
Dependent Claim
82 words
A vacuum interrupter device 11, comprising a pair of dense, sintered contacts 21 and 27 movable into either a closed circuit contact with each other or an open circuit, spaced relation relative to each other, said contacts obtained by sintering in an atmosphere partly oxidative to chromium and reductive to copper and bismuth, a mixture comprising 50 to 75 weight percent coopper, 15 to 30 weight percent chromium, 2.5 to 15 weight percent bismuth, and 0.5 to 7.5 weight percent chromic oxide.
Claim 16
Dependent Claim
22 words
The vacuum interrupter device according to claim 10, wherein the mixture includes from 1 to 3 percent by weight of chromic oxide.
Claim 17
Independent Claim
87 words
A method of making a vacuum interrupter contact comprising the steps of: (A) providing a mixture comprising: (a) 50 to 75 weight percent copper, (b) 15 to 30 weight percent chromium, (c) 2.5 to 15 weight percent bismuth, and (d) 0.5 to 7.5 weight percent chromic oxide, (B) cold pressing the mixture to form a contact briquette, (C) sintering the briquette in a flow of a gas that contains water vapor, so that chromium is oxidized, to produce a dense contact, and (D) cooling the sintered contact.
Claim 18
Independent Claim
87 words
A method of making a vacuum interrupter contact comprising the steps of: (A) providing a mixture comprising: (a) 50 to 75 weight percent copper, (b) 15 to 30 weight percent chromium, (c) 2.5 to 15 weight percent bismuth, and (d) 0.5 to 7.5 weight percent chromic oxide, (B) cold pressing the mixture to form a contact briquette, (C) sintering the briquette in a flow of a gas that contains water vapor, so that chromium is oxidized, to produce a dense contact, and (D) cooling the sintered contact.
Claim 19
Dependent Claim
19 words
The method of claim 12, where the mixture includes from 1 to 3 percent by weight of chromic oxide.
Claim 20
Dependent Claim
38 words
The method of claim 12, where the gas is hydrogen gas, water vapor is present in the hydrogen gas at over 0.006 volume percent, and sintering is carried out at from about 750° C. to about 1000° C.
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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) | 1991-05-10 | 1991-11-09 | 1992-05-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-10 | 1995-11-09 | 1996-05-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-10 | 1999-11-09 | 2000-05-10 | $7700.00 | Window Closed / Lapsed |