US3994174A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for measuring the density of liquids
Assignee: KALLE-REGULATORER AB
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Filing: 1975-03-20
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Granted: 1976-11-30
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Expires: 1995-03-20
Abstract
Abstract A device for measuring the density of liquids. A float provided with a piece of soft iron on one side and with a permanent magnet on the other side is movably disposed in a housing through which a liquid may flow. The soft iron is surrounded by a differential winding, and the permanent magnet is surrounded by two windings with opposing fluxes and having substantially the same numbers of ampere-turns. An output lead from the differential winding is connected to the windings surrounding the permanent magnet over an amplifier. A measuring instrument connected between the amplifier and the windings surrounding the permanent magnet provides an indication of the density of the liquid flowing through said housing.
Inventors
- 👤 Lennart Ekman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 08:42
CPC Classifications
C; C04; C04B; C04B38/00; C04B38/06; G; G01; G01N; G01N9/00; G01N9/10; G01N9/20; G01N9/22
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
176 words
In a device for measuring the density of liquids having a housing with a fluid inlet and a fluid outlet, said fluid inlet and fluid outlet being operably coupled to a conduit carrying the liquid whose density is to be measured, a movable float disposed in said housing having an armature at one end and a permanent magnet at the other end thereof, a differential transformer positioned in said housing surrounding said armature, a source of electrical power coupled to one side of said differential transformer, the improvement comprising: rectifier means coupled to the other side of said differential transformer, an amplifier coupled to said rectifier, a pair of windings with opposing fluxes, each having substantially the same number of ampere turns surrounding said permanent magnet and coupled to said amplifier wherein rectified current produced as a result of movement of said armature relative to said differential transformer is supplied to said pair of windings to restore said permanent magnet to a position of equilibrium relative to said pair of windings without demagnetizing said permanent magnet.
Claim 2
Dependent Claim
176 words
In a device for measuring the density of liquids having a housing with a fluid inlet and a fluid outlet, said fluid inlet and fluid outlet being operably coupled to a conduit carrying the liquid whose density is to be measured, a movable float disposed in said housing having an armature at one end and a permanent magnet at the other end thereof, a differential transformer positioned in said housing surrounding said armature, a source of electrical power coupled to one side of said differential transformer, the improvement comprising: rectifier means coupled to the other side of said differential transformer, an amplifier coupled to said rectifier, a pair of windings with opposing fluxes, each having substantially the same number of ampere turns surrounding said permanent magnet and coupled to said amplifier wherein rectified current produced as a result of movement of said armature relative to said differential transformer is supplied to said pair of windings to restore said permanent magnet to a position of equilibrium relative to said pair of windings without demagnetizing said permanent magnet.
Claim 3
Dependent Claim
23 words
A device in accordance with claim 1, wherein a measuring instrument is connected between the amplifier and the windings surrounding the permanent magnet.
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) | 1979-11-30 | 1980-05-31 | 1980-11-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-11-30 | 1984-05-31 | 1984-11-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-11-30 | 1988-05-31 | 1988-11-30 | $7700.00 | Window Closed / Lapsed |