US5142267A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Level sensor which has high signal gain and can be used for fluids particularly chemically corrosive fluids
Assignee: Siemens AG
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Filing: 1990-05-11
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Granted: 1992-08-25
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Expires: 2010-05-11
Abstract
Abstract A PTC-resistor which is a temperature dependent electrical thermistor of semiconductor ferro-electric ceramic which is provided with power leads and serves as a sensor element is directly fused into glass. The power leads are welded to metal coatings formed on the PTC-resistor which are stable at the temperature occurring when the PTC-resistor is fused. The metal coatings are made of aluminum which are formed by aluminum silk screened metallizations which have a thickness of 50 μm or more.
Inventors
- 👤 Siegfried Fellner
- 👤 Gerhard Bisail
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 23:18
CPC Classifications
G; G01; G01F; G01F23/00; G01F23/22; G01F23/24; G01F23/246
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
92 words
A level sensor for liquids, particularly chemically aggressive liquids, comprising a PTC-resistor that is provided with leads and is mounted in a glass sheath to form a sensor element, whereby the leads are welded to metal coatings on the PTC-resistor, the improvement comprising, wherein said metal coatings of the PTC-resistor are aluminum which are silk screened metallizations; and in that the PTC-resistor together with the aluminum silk screened metallizations and leads are directly fused into said glass sheath, so that direct intimate contact is made between said PTC-resistor and the fused glass.
Claim 2
Dependent Claim
92 words
A level sensor for liquids, particularly chemically aggressive liquids, comprising a PTC-resistor that is provided with leads and is mounted in a glass sheath to form a sensor element, whereby the leads are welded to metal coatings on the PTC-resistor, the improvement comprising, wherein said metal coatings of the PTC-resistor are aluminum which are silk screened metallizations; and in that the PTC-resistor together with the aluminum silk screened metallizations and leads are directly fused into said glass sheath, so that direct intimate contact is made between said PTC-resistor and the fused glass.
Claim 3
Dependent Claim
21 words
A level sensor according to claim 1, characterized in that said aluminum silk screened metallizations have thicknesses of approvimately 50 μm.
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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) | 1995-08-25 | 1996-02-24 | 1996-08-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-08-25 | 2000-02-24 | 2000-08-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-08-25 | 2004-02-24 | 2004-08-25 | $7700.00 | Window Closed / Lapsed |