Patent US1229482A successfully refreshed from Google Patents.
Patent US4080663A successfully refreshed from Google Patents.
US4080663A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic stirrer
Assignee: Individual
•
Filing: 1977-03-07
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Granted: 1978-03-21
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Expires: 1997-03-07
Abstract
Abstract A magnetic stirrer for stirring a fluid in a vessel where a stirring rotor in form of a permanent bar magnet is easily movable for rotation by means of an externally applied rotating magnet field. Said field is set up by four magnet coils arranged in a parallel relationship to form a square configuration and fed by respective phase-shifted a.c. currents, the common center axis of the coils being aligned with the rotor in the overlying vessel. A plate of mu-metal is arranged in said center axis and adjacent the bottom of the vessel to concentrate the longitudinal magnet flow lines of the coils for interaction with the flow lines of the rotor to maintain the rotor centered.
Inventors
- 👤 Gunnar Wik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 16:35
CPC Classifications
B; B01; B01F; B01F33/00; B01F33/45; B01F33/452; B01F35/00; B01F35/20
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
123 words
A magnetic stirrer comprising a stirring rotor in form of a permanent bar magnet which is easily movable in a vessel containing a fluid to be stirred, at least one pair of parallelly disposed magnet coils, supplied with respective phase-shifted a.c. currents to induce opposite magnetomotive forces in said coils, resulting in a rotating magnet field, said vessel being positioned near the top plane of said coils and having the rotor substantially aligned with the common centre axis of the coils, so that the rotor is rotated by said rotating magnet field, a plate of a soft-magnetic material having magnetic shielding properties, such as mu-metal, being positioned adjacent the bottom of said vessel and substantially in said common centre axis of the coils.
Claim 2
Dependent Claim
123 words
A magnetic stirrer comprising a stirring rotor in form of a permanent bar magnet which is easily movable in a vessel containing a fluid to be stirred, at least one pair of parallelly disposed magnet coils, supplied with respective phase-shifted a.c. currents to induce opposite magnetomotive forces in said coils, resulting in a rotating magnet field, said vessel being positioned near the top plane of said coils and having the rotor substantially aligned with the common centre axis of the coils, so that the rotor is rotated by said rotating magnet field, a plate of a soft-magnetic material having magnetic shielding properties, such as mu-metal, being positioned adjacent the bottom of said vessel and substantially in said common centre axis of the coils.
Claim 3
Dependent Claim
55 words
A magnetic stirrer according to claim 1, comprising two pairs of coils arranged in a substantially square formation, each pair being supplied from a different phase line of an a.c. voltage source, the plate of mu-metal being provided in the common centre area of the four coils and located adjacent the bottom of said vessel.
Claim 4
Dependent Claim
69 words
A magnetic stirrer according to claim 2, comprising an additional pair of coils forming, together with one of the two remaining pairs, another square formation, said additional pair of coils having a phase supply line common with the other of these coil pairs, a second plate of mu-metal being positioned in the central area of said additional square formation to act upon a rotor in a second overlying vessel.
Claim 5
Dependent Claim
33 words
A magnetic stirrer according to claim 1, wherein disks of mu-metal also are placed over each of the coils, said disks being of a size to cover the top surface of said coils.
References Cited (Backward Citations)
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Cited
US3206172A
Cited
GB1156206A
Cited
US3680843A
Cited
US3749369A
Cited
US3985649A
Cited
US3997272A
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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) | 1981-03-20 | 1981-09-19 | 1982-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-03-20 | 1985-09-19 | 1986-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-03-20 | 1989-09-19 | 1990-03-21 | $7700.00 | Window Closed / Lapsed |