US3693941A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electromagnetically propelled stirrer and shaker
Assignee: Individual
•
Filing: 1971-08-23
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Granted: 1972-09-26
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Expires: 1991-08-23
Abstract
Abstract A motorless laboratory magnetic stirrer is composed from two fixed electromagnets whose magnetic poles lie in a common plane and are perpendicular to each other. Both electromagnets are supplied by alternating currents of adjustable, but equal, low frequency mutually phase-shifted by 90*, which are produced by a controlled switching of the network current. The angular velocity of the rotating magnetic field produced in this way equals the frequency of the supplying current and acts to rotate a magnetic rod in a liquid. In a similar way a magnetically propelled shaker is constructed. Two permanent magnets perpendicular to each other are fixed to a tray and placed close to the electromagnets mentioned above. The tray is attached to a base in a manner which permits its free movement in the plane of the tray without rotation of the tray. The tray then exercises an orbital movement and acts to shake a liquid in a vessel placed on the tray. To obtain higher force for shaking, the principles of attracting two permanent magnets by stationary electromagnets is replaced by solenoids, attracting ferromagnetic cores.
Inventors
- 👤 Jan S Suchy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 00:01
CPC Classifications
B; B01; B01F; B01F33/00; B01F33/45; B01F33/452; B01F35/00; B01F35/20
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
116 words
Electromagnetic means for causing a movement in a laboratory reaction the such as a beaker, comprising two stationary linear electromagnetic devices arranged with pairs of coils lying in a common plane at right angles to each other, means for supplying alternating currents to said magnetic devices at adjustable but equal low frequencies, means for causing phase-shifting of said currents between said two magnetic devices by 90* , and a support above said electromagnetic devices, whereby a beaker or other liquid filled container may rest upon said support and movement in the liquid will be caused responsive to the rotating magnetic field of said magnetic devices at an angular velocity determined by the adjustment of said frequencies.
Claim 2
Dependent Claim
116 words
Electromagnetic means for causing a movement in a laboratory reaction the such as a beaker, comprising two stationary linear electromagnetic devices arranged with pairs of coils lying in a common plane at right angles to each other, means for supplying alternating currents to said magnetic devices at adjustable but equal low frequencies, means for causing phase-shifting of said currents between said two magnetic devices by 90* , and a support above said electromagnetic devices, whereby a beaker or other liquid filled container may rest upon said support and movement in the liquid will be caused responsive to the rotating magnetic field of said magnetic devices at an angular velocity determined by the adjustment of said frequencies.
Claim 3
Dependent Claim
104 words
Electromagnetic means as defined in claim 1, wherein said movement is orbital motion of a tray carrying a beaker and resting upon said support, and wherein said stationary magnetic devices comprise two pairs of opposing solenoids, and four cores one for each of said solenoids, said cores connected to said tray and consecutively attracted by said four solenoids in a cycle, whereby a fermentation flask or other liquid filled container may rest upon said tray and will be caused to exercise an orbital motion responsive to the energizing of said four solenoids sequentially at said angular velocity determined by the adjustment of said frequencies.
Claim 4
Dependent Claim
70 words
Electromagnetic means as defined in claim 1, wherein said movement is the rotation of a magnetic rod as a stirrer in a liquid filled beaker resting upon said support, and wherein said stationary magnetic devices are tow electromagnets, whereby a magnetic rod in the liquid two be caused to rotate responsive to the rotating magnetic field of said magnets at said angular velocity determined by the adjustment of said frequencies.
Claim 5
Dependent Claim
84 words
Electromagnetic means as defined in claim 3, wherein each of said current switching devices is a bidirectional thyristor, each of said triggering circuits includes a unijunction transistor having an charging circuit including a resistance and a capacitance in series arranged to provide a long charging period in the triggering circuit than in the other, and a connection between said triggering circuits causing discharge of the capacitance in said other triggering circuit simultaneously with the firing of said unijunction transistor in said one triggering circuit.
Claim 6
Dependent Claim
127 words
Electromagnetic means as defined in claim 1 for rotating a magnetic field, wherein said means for causing phase shifting of said currents to the coils of said two electromagnetic devices comprises an alternating current source in two circuits one respectively with each pair of said coils, a current switching device in each of said circuits of a type adapted to be triggered by an impulse, a triggering circuit in circuit with each of said current switching devices including a power source adapted to provide said impulse, and including a time-delay device in one of said triggering circuits causing the same to reach critical voltage in a time period one-third longer than the time period required in the other of said triggering circuits to reach said critical voltage.
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) | 1975-09-26 | 1976-03-27 | 1976-09-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-09-26 | 1980-03-27 | 1980-09-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-09-26 | 1984-03-27 | 1984-09-26 | $7700.00 | Window Closed / Lapsed |