US4749416A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Immersion pyrometer with protective structure for sidewall use
Assignee: Vesuvius Crucible Co
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Filing: 1986-08-01
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Granted: 1988-06-07
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Expires: 2006-08-01
Abstract
Abstract Temperature sensing apparatus for use in the sidewall or bottom of a vessel for containing molten metal. A temperature sensing element is mounted within a sheath which is provided with a sacrificial coating to protect the sheath from premature oxidation such as may occur during a gas-flame pre-heat cycle. The sheath which is being protected against premature oxidation by the sacrificial coating is a composite of a closed end metal tube and a plurality of porous cermet layers of aluminum oxide-chromium oxide-molybdenum with the concentration of molybdenum decreasing in proceeding from the inner cermet layer to the outer cermet layer. The outer cermet layer of the sheath is covered by a ceramic layer of aluminum oxide. The sacrificial coating consists of a layer of zirconium oxide in combination with and covered by a layer of fibrous alumina. The sacrificial coating is typically destroyed by the end of a pre-heat cycle.
Inventors
- 👤 David C. Greenspan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 02:58
CPC Classifications
G; G01; G01K; G01K1/00; G01K1/08; G01K1/12; G01K1/10; G01K1/105
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
138 words
Temperature sensing apparatus comprising: a temperature sensing element; a sheath for enclosing said temperature sensing element, said sheath comprising a closed end metal tube, a plurality of protective layers covering said metal tube, said protective layers comprising at least two cermet layers consisting of aluminum oxide-chromium oxide-molybdenum, the concentration of molybdenum in said cermet layers decreasing in proceeding from the inner to the outer layers, and a ceramic layer of substantially pure aluminum oxide-chromium oxide covering the outermost cermet layers, each of said cermet layers and said ceramic layer having a porosity of from about 4 percent to about 33 percent; and Sacrificial outer lamella covering at least a portion of said sheath, said lamella comprising a layer of zirconia in combination with and covered by a layer of fibrous alumina, thereby protecting said sheath from premature oxidation.
Claim 2
Dependent Claim
138 words
Temperature sensing apparatus comprising: a temperature sensing element; a sheath for enclosing said temperature sensing element, said sheath comprising a closed end metal tube, a plurality of protective layers covering said metal tube, said protective layers comprising at least two cermet layers consisting of aluminum oxide-chromium oxide-molybdenum, the concentration of molybdenum in said cermet layers decreasing in proceeding from the inner to the outer layers, and a ceramic layer of substantially pure aluminum oxide-chromium oxide covering the outermost cermet layers, each of said cermet layers and said ceramic layer having a porosity of from about 4 percent to about 33 percent; and Sacrificial outer lamella covering at least a portion of said sheath, said lamella comprising a layer of zirconia in combination with and covered by a layer of fibrous alumina, thereby protecting said sheath from premature oxidation.
Claim 3
Dependent Claim
19 words
Temperature sensing apparatus in accordance with claim 1 wherein said sheath contains at least one layer of boron nitride.
Claim 4
Dependent Claim
24 words
Temperature sensing apparatus in accordance with claim 1 wherein said sheath and said sacrificial outer lamella are separated by a layer of boron nitride.
Claim 5
Dependent Claim
27 words
Temperature sensing apparatus in accordance with claim 1 secured within a tubular shell by a castable refractory, and said tubular shell is mounted within a refractory brick.
Claim 6
Dependent Claim
20 words
Temperature sensing apparatus in accordance with claim 4 wherein said tubular shell is tapered and is made of stainless steel.
Claim 7
Dependent Claim
20 words
Temperature sensing apparatus in accordance with claim 1 wherein the closed end metal tube is lined with a ceramic sleeve.
Claim 8
Dependent Claim
16 words
Temperature sensing apparatus in accordance with claim 1 wherein the closed end metal tube comprises molybdenum.
Claim 9
Dependent Claim
17 words
Temperature sensing apparatus in accordance with claim 1, wherein the metal tube is made of stainless steel.
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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) | 1991-06-07 | 1991-12-07 | 1992-06-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-06-07 | 1995-12-07 | 1996-06-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-06-07 | 1999-12-07 | 2000-06-07 | $7700.00 | Window Closed / Lapsed |