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US3855559A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic position detectors, notably level detectors
Assignee: PETROLE SERVICE SA
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Filing: 1973-12-03
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Granted: 1974-12-17
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Expires: 1993-12-03
Abstract
Abstract A magnetic detection device for detecting the position of a movable member of the type comprising a piece of magnetic material associated with the movement of the movable member and capable of moving within a tube of non-magnetic material, and at least one detector unit disposed in a fixed manner with respect to the tube and externally thereof, and formed of a permanent magnet the poles of which are directed towards the tube, and a a flexible knife switch fixed immediately adjacent to the magnet. According to the invention, the tube is surrounded with a ring of magnetic material integral with the two poles of the magnet, so that it is possible to use a permanent magnet which is much less powerful than the magnets of known devices while obtaining a variation in intensity of at least 50 percent of the intensity of the magnetic field in the flexible knife switch when the part made of magnetic material arrives at the level of the ring or moves away from it.
Inventors
- 👤 J Lenseigne
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 07:02
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/12; G01D5/25; G01D5/251; G01D5/2515; G01F; G01F23/00; G01F23/30; G01F23/56
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
89 words
A magnetic detection device for detecting the position of a movable member comprising a nonmagnetic tube, a piece of magnetic material operatively connected to said member and movable within said tube in accordance with the movement of said member, a detector unit situated external to said tube comprising a permanent magnet the poles of which are situated on either side of said tube and a ring of magnetic material surrounding said tube and integral with the poles of said magnet, and a flexible knife switch located adjacent said magnet.
Claim 2
Dependent Claim
89 words
A magnetic detection device for detecting the position of a movable member comprising a nonmagnetic tube, a piece of magnetic material operatively connected to said member and movable within said tube in accordance with the movement of said member, a detector unit situated external to said tube comprising a permanent magnet the poles of which are situated on either side of said tube and a ring of magnetic material surrounding said tube and integral with the poles of said magnet, and a flexible knife switch located adjacent said magnet.
Claim 3
Dependent Claim
22 words
The device of claim 1 wherein said magnet has a substantially U-shape and wherein said ring is mounted to the extremities thereof.
Claim 4
Dependent Claim
20 words
The device of claim 2 wherein said knife switch is seCured adjacent said magnet parallel to the bar portion thereof.
Claim 5
Dependent Claim
13 words
The device of claim 1 wherein said ring has a longitudinal slot therein.
Claim 6
Dependent Claim
40 words
The device of claim 1 wherein said ring has two opposed slots situated in the plane containing the axis of the ring and substantially perpendicular to the axis joining the extremities of the two magnetic poles of said permanent magnet.
Claim 7
Dependent Claim
40 words
The device of claim 4 further comprising a pair of tabs each of which is mounted to a different one of the edges of said slot and means for connecting said tabs together to secure said ring to said tube.
Claim 8
Dependent Claim
42 words
The device of claim 5 further comprising a pair of tabs each of which is mounted to a different one of the edges of one of said slots and means for connecting said tabs together to secure said ring to said tube.
Claim 9
Dependent Claim
14 words
The device of claim 1 wherein said piece of magnetic material comprises ferro-magnetic material.
Claim 10
Dependent Claim
14 words
The device of claim 1 wherein said ring is made of a soft steel.
Claim 11
Dependent Claim
31 words
The device of claim 1 further comprising an auxiliary permanent magnet secured parallel to said switch and adjacent thereto in order to annul or oppose the effect of said permanent magnet.
Claim 12
Dependent Claim
43 words
The device of claim 1 further comprising a liquid whose level is to be monitored, said movable member being adopted to float on the surface of said liquid and a nonmagnetic rod connected between said movable member and said piece of magnetic material.
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) | 1977-12-16 | 1978-06-17 | 1978-12-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-16 | 1982-06-17 | 1982-12-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-16 | 1986-06-17 | 1986-12-17 | $7700.00 | Window Closed / Lapsed |