US4576725A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic fluid incorporating fine magnetic powder and method for making the same
Assignee: Toyota Motor Corp
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Filing: 1984-06-13
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Granted: 1986-03-18
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Expires: 2004-06-13
Abstract
Abstract A magnetic fluid having a base liquid and magnetic particles with so small average particle diameter as to be of some hundreds of angstroms dispersed in the base liquid. Such a magnetic fluid is produced by ejecting a molten magnetic metal adiabatically from an expansion nozzle against a bath of a base liquid.
Inventors
- 👤 Hirohisa Miura
- 👤 Hiroshi Satou
- 👤 Hidenori Katagiri
- 👤 Toshio Natsume
- 👤 Hidekazu Azuma
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:52
CPC Classifications
B; B22; B22F; B22F9/00; B22F9/02; B22F9/12; B22F1/00; B22F1/05; B22F1/054; B22F1/0545; B82; B82Y; B82Y30/00; H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/032; H01F1/04; H01F1/06; H01F1/066; H01F1/12; H01F1/14; H01F1/20; H01F1/28; H01F1/44; H01F1/442; B22F2998/00
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
63 words
A magnetic fluid, comprising a base liquid and metallic magnetic particle with average particle diameter of some hundreds of angstroms dispersed therein, said metallic magnetic particles each being suspended in said base liquid as each being directly generated from a metallic vapor through rapid cooling by adiabiatic expansion of said metallic vapor and thereafter directly introduced into a bath of said base liquid.
Claim 2
Dependent Claim
63 words
A magnetic fluid, comprising a base liquid and metallic magnetic particle with average particle diameter of some hundreds of angstroms dispersed therein, said metallic magnetic particles each being suspended in said base liquid as each being directly generated from a metallic vapor through rapid cooling by adiabiatic expansion of said metallic vapor and thereafter directly introduced into a bath of said base liquid.
Claim 3
Dependent Claim
21 words
A magnetic fluid according to claim 1, wherein said magnetic particles have average particle diameter of less than two hundred angstroms.
Claim 4
Dependent Claim
15 words
A magnetic fluid according to clam 1, wherein said magnetic particles are made of iron.
Claim 5
Dependent Claim
15 words
A magnetic fluid according to clam 1, wherein said magnetic particles are made of iron.
Claim 6
Dependent Claim
18 words
A magnetic fluid according to claim 1, wherein said magnetic particles are made of a cobalt and samarium.
Claim 7
Dependent Claim
17 words
A magnetic fluid according to claim 1, wherein said magnetic particles are made of cobalt and nickel.
Claim 8
Independent Claim
78 words
A method for making magnetic fluid comprising a base liquid and metallic magnetic particles with average particle diameter of some hundred angstrums dispersed therein, comprising the steps of: preparing a quantity of high temperature stable vapor of a metal, directing said vapor through an expansion nozzle means for adiabatic expansion cooling thereof enough to condense said vapor into particles of said diameter, and directing an output flow from said nozzle means against a quantity of said base liquid.
Claim 9
Independent Claim
78 words
A method for making magnetic fluid comprising a base liquid and metallic magnetic particles with average particle diameter of some hundred angstrums dispersed therein, comprising the steps of: preparing a quantity of high temperature stable vapor of a metal, directing said vapor through an expansion nozzle means for adiabatic expansion cooling thereof enough to condense said vapor into particles of said diameter, and directing an output flow from said nozzle means against a quantity of said base liquid.
Claim 10
Dependent Claim
23 words
A method according to claim 6, wherein said metal vapor is mixed with a carrier gas before being passed through said nozzle means.
Claim 11
Dependent Claim
22 words
A method according to claim 6, wherein said quantity of base liquid is agitated while said output flow is being directed thereagainst.
Claim 12
Dependent Claim
24 words
A method according to claim 6, wherein said metal vapor is mixed with vapor of another metal before being passed through said nozzle means.
Claim 13
Dependent Claim
39 words
A method according to claim 9, wherein said metal vapor is passed through another expansion nozzle means for adiabatic expansion cooling before being mixed with said vapor of said another metal and before being passed through said nozzle means.
Claim 14
Dependent Claim
59 words
A method according to claim 6, wherein vapor of another metal is also passed through another expansion nozzle means for adiabatic expansion cooling and the output flow from said another nozzle means is directed so as to merge with said output flow from said nozzle means, before the combined flow thereof impinges against said quantity of said base liquid.
References Cited (Backward Citations)
US3531413A
Cited
US3700575A
Cited
US3635819A
Cited
US3806449A
Cited
US4234437A
Cited
US3764540A
Cited
US3917538A
Cited
US4094804A
Cited
US3981844A
Cited
US4019994A
Cited
US4208294A
Cited
US4329241A
Cited
US4315827A
Cited
US4356098A
Cited
US4280918A
Cited
US4381244A
Cited
US4430239A
Cited
US4416721A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-03-17 | 1989-09-16 | 1990-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-03-17 | 1993-09-16 | 1994-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-03-17 | 1997-09-16 | 1998-03-18 | $7700.00 | Window Closed / Lapsed |