US4606807A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Probe for measuring the carbon potential of endothermic gas
Assignee: Individual
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Filing: 1985-05-24
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Granted: 1986-08-19
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Expires: 2005-05-24
Abstract
Abstract An oxygen probe for measuring the carbon potential of endothermic gas in a heat treating furnace. The probe uses a readily available, automative-type oxygen sensor having a solid electrolyte element. The sensor is mounted on a heat conducting base plate. The sensor element is surrounded by a gas flow tube extending from the base plate. Exit ports around the base of the sensor element extend through the base plate and into the area defined by the gas flow tube causing an axial, radially symmetric flow of gas around the sensor element. The tip of the element is heated above the temperature of the gas while the base of the element is conductively cooled by the base plate. A temperature gradient is thus caused along the length of the sensor element, increasing its sensitivity.
Inventors
- 👤 Donald H. Mendenhall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 13:19
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/0004; G01N33/0009; G01N33/0027; G01N33/0036; G01N33/004; G01N27/00; G01N27/26; G01N27/403; G01N27/406; G01N27/4067
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
389 words
An oxygen probe attachable to an auxiliary outlet of a heat treating furnace for measuring the carbon potential of endothermic heat treating gas within the furnace, comprising: a replaceable oxygen sensor having an elongated, solid electrolyte element, the element being hollow at a base end and closed at the tip, the base of the element supported by a threaded portion on the sensor, the inner surface of the element being exposable to a reference gas and the outer surface of the element being exposable to the endothermic gas to be measured such that an electric potential is generated between the surfaces of the element in proportion to the carbon potential of the measured endothermic gas; a base plate defining an aperture around the threaded portion of the sensor so that the sensor element protrudes through the aperture, the base plate having at least two substantially diametrically opposed exit ports extending through the base plate, and radially spaced from the center of the aperture for venting endothermic gas away from the base of the sensor element; a gas flow tube connected by one of its ends to the base plate and substantially coaxially aligned with the sensor element, the inner wall of the gas flow tube enclosing the sensor element and the exit ports, the other end of the gas flow tube having means for joining the gas flow tube to the auxiliary outlet of the furnace, the gas flow tube and the exit ports causing an axial, substantially radially symmetrical gas flow path around the sensor element for substantially the entire length of the senor element, including means for catalyzing the endothermic gas within the gas flow tube to reduce soot deposits within the tube; a controllable annular heater having an inner surface contacting the outer wall of the gas flow tube and having one end towards the base plate and the other end extending therefrom approximately twice the length of the sensor element so that the tip of the sensor element is positioned along the midsection of the heater; means for measuring the temperature of the midsection of the heater to determine the temperature of the tip of the sensor element; and means for maintaining the measured temperature of the tip of the sensor element greater than the temperature of the endothermic gas entering the gas flow tube.
Claim 2
Dependent Claim
389 words
An oxygen probe attachable to an auxiliary outlet of a heat treating furnace for measuring the carbon potential of endothermic heat treating gas within the furnace, comprising: a replaceable oxygen sensor having an elongated, solid electrolyte element, the element being hollow at a base end and closed at the tip, the base of the element supported by a threaded portion on the sensor, the inner surface of the element being exposable to a reference gas and the outer surface of the element being exposable to the endothermic gas to be measured such that an electric potential is generated between the surfaces of the element in proportion to the carbon potential of the measured endothermic gas; a base plate defining an aperture around the threaded portion of the sensor so that the sensor element protrudes through the aperture, the base plate having at least two substantially diametrically opposed exit ports extending through the base plate, and radially spaced from the center of the aperture for venting endothermic gas away from the base of the sensor element; a gas flow tube connected by one of its ends to the base plate and substantially coaxially aligned with the sensor element, the inner wall of the gas flow tube enclosing the sensor element and the exit ports, the other end of the gas flow tube having means for joining the gas flow tube to the auxiliary outlet of the furnace, the gas flow tube and the exit ports causing an axial, substantially radially symmetrical gas flow path around the sensor element for substantially the entire length of the senor element, including means for catalyzing the endothermic gas within the gas flow tube to reduce soot deposits within the tube; a controllable annular heater having an inner surface contacting the outer wall of the gas flow tube and having one end towards the base plate and the other end extending therefrom approximately twice the length of the sensor element so that the tip of the sensor element is positioned along the midsection of the heater; means for measuring the temperature of the midsection of the heater to determine the temperature of the tip of the sensor element; and means for maintaining the measured temperature of the tip of the sensor element greater than the temperature of the endothermic gas entering the gas flow tube.
Claim 3
Dependent Claim
112 words
The probe of claim 1, wherein the base plate is in thermally conductive communication with the base of the sensor element and wherein the base plate has a sufficient mass and surface area to conduct heat energy from the base of the sensor element and wherein the probe further includes means for thermally insulating the annular heater from the base plate to maintain the temperature of the base plate substantially below the temperature of the tip of the sensor element, thereby causing an axial temperature gradient across the sensor element from the tip to the base thereof for increasing the potential difference generated by the sensor element when the probe is operating.
Claim 4
Dependent Claim
22 words
The probe of claim 1 wherein the catalyzing means comprises a coil having a plurality of turns of high nickel content wire.
Claim 5
Dependent Claim
15 words
The probe of claim 3 wherein the wire has a nickel content of approximately 80%.
Claim 6
Dependent Claim
62 words
The probe of claim 1, comprising four exit ports at 90-degree intervals around the base of the element and between the outer surface of the sensor element and the inner wall of the gas flow tube, for causing a radially uniform, axial flow of endothermic gas around the sensor element from the tip of the element to the base of the element.
Claim 7
Dependent Claim
300 words
An oxygen probe housing attachable to an auxiliary outlet of a heat treating furnace utilizing a replaceable oxygen sensor having a solid zirconium oxide electrolyte element comprising: a heat-conducting base plate defining an aperture around the oxygen sensor so that the sensor element protrudes through the center of the aperture, the base plate further having at least two substantially diametrically opposed exit ports extending therethrough and radially spaced from the center of the aperture for venting endothermic gas away from the area around the aperture; a gas flow tube having one end connected to the base plate so as to be coaxial with a line perpendicular to the base plate and passing through the center of the aperture, the inner wall of the tube enclosing the aperture and the exit ports, the other end of the gas flow tube having means for joining the gas flow tube to an auxiliary outlet of the furnace, the gas flow tube and the exit ports defining an axial, substantially radially symmetrical gas flow path around the sensor element, including means for catalyzing the endothermic gas within the gas flow tube to reduce soot deposits within the tube; a controllable annular heater having an inner surface contacting the outer wall of the gas flow tube and having one end towards the base plate and the remaining end extending away from the base plate approximately twice the length of the sensor element to locate the tip of the sensor element at approximately the midsection of the heater; means for measuring the temperature of the midsection of the heater and to determine the temperature of the tip of the sensor element; and means for maintaining the measured temperature of the sensor element tip greater than the temperature of the endothermic gas entering the gas flow tube.
Claim 8
Dependent Claim
300 words
An oxygen probe housing attachable to an auxiliary outlet of a heat treating furnace utilizing a replaceable oxygen sensor having a solid zirconium oxide electrolyte element comprising: a heat-conducting base plate defining an aperture around the oxygen sensor so that the sensor element protrudes through the center of the aperture, the base plate further having at least two substantially diametrically opposed exit ports extending therethrough and radially spaced from the center of the aperture for venting endothermic gas away from the area around the aperture; a gas flow tube having one end connected to the base plate so as to be coaxial with a line perpendicular to the base plate and passing through the center of the aperture, the inner wall of the tube enclosing the aperture and the exit ports, the other end of the gas flow tube having means for joining the gas flow tube to an auxiliary outlet of the furnace, the gas flow tube and the exit ports defining an axial, substantially radially symmetrical gas flow path around the sensor element, including means for catalyzing the endothermic gas within the gas flow tube to reduce soot deposits within the tube; a controllable annular heater having an inner surface contacting the outer wall of the gas flow tube and having one end towards the base plate and the remaining end extending away from the base plate approximately twice the length of the sensor element to locate the tip of the sensor element at approximately the midsection of the heater; means for measuring the temperature of the midsection of the heater and to determine the temperature of the tip of the sensor element; and means for maintaining the measured temperature of the sensor element tip greater than the temperature of the endothermic gas entering the gas flow tube.
Claim 9
Dependent Claim
72 words
The probe of claim 6, wherein the probe further includes means for thermally insulating the annular heater from the base plate to maintain the temperature of the base plate substantially below the temperature of the tip of the sensor element, thereby causing an axial temperature gradient across the sensor element from the tip to the base thereof for increasing the potential difference generated by the sensor element when the probe is operating.
Claim 10
Dependent Claim
22 words
The probe of claim 6 wherein the catalyzing means comprises a coil having a plurality of turns of high nickel content wire.
Claim 11
Dependent Claim
15 words
The probe of claim 8 wherein the wire has a nickel content of approximately 80%.
Claim 12
Dependent Claim
25 words
The probe of claim 6 comprising four exit ports at approximately 90-degree intervals between the aperture and the inner wall of the gas flow tube.
References Cited (Backward Citations)
US3598711A
Cited
US3597345A
Cited
US3699032A
Cited
US4005001A
Cited
US4247380A
Cited
US4098650A
Cited
US4115229A
Cited
US4175019A
Cited
US4184934A
Cited
US4339318A
Cited
US4430192A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-08-18 | 1990-02-17 | 1990-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-08-18 | 1994-02-17 | 1994-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-08-18 | 1998-02-17 | 1998-08-19 | $7700.00 | Window Closed / Lapsed |