Claims
- 1. A sensor for simultaneously monitoring temperatures of a plurality of regions within a tube, and providing a signal indicative of the temperature in a hottest one of said plurality of regions, comprising:
- first and second metal electrodes, both electrodes having a first length and essentially consisting of the same metal, which are parallel and spaced apart at a fixed distance, each electrode extending over the regions to be monitored within the tube;
- wherein said first electrode (27-1) extends along a central axis of said tube and said second electrode (27-2) extends parallel thereto;
- a third electrode (27-3) having a second length which is shorter than said first length and extending parallel to the first electrode within the tube;
- a fourth electrode (27-4) having a third length which is shorter than said second length and extending parallel to said first electrode within said tube;
- wherein said second, third and fourth electrodes define a radial array surrounding said first electrode;
- an insulating substance (2) filling the volume between said electrodes and extending over the regions to be monitored, said insulating substance having a resistivity which continuously decreases with increasing temperature, within a temperature range to be monitored which is between 800.degree. C. and a melting point of the electrodes, said substance remaining solid over said range; and
- wherein current flowing from one electrode, through the insulating substance, to another electrode, is shunted to the region having a highest temperature, due to a lower resistance of the insulating substance in said region having the highest temperature, thereby providing an output signal corresponding to resistance of said region having the highest temperature.
- 2. A sensor for monitoring temperature, as recited in claim 1, wherein said temperature range to be monitored is between 800 and 1500 degrees centigrade.
- 3. A sensor for monitoring temperature, as recited in claim 1, wherein said insulating substance consists essentially of one of magnesium oxide and high purity alumina.
- 4. A sensor according to claim 1, wherein said metal electrodes are opposed to each other only within a particular region within the monitoring range of the refractory.
- 5. A sensor according to ciaim 1, wherein said metal electrodes are a pair of metal plates having a high melting point and disposed in a parallel opposing relationship to each other.
Priority Claims (4)
Number |
Date |
Country |
Kind |
1-135756 |
May 1989 |
JPX |
|
1-135757 |
May 1989 |
JPX |
|
1-135758 |
May 1989 |
JPX |
|
1-155594 |
Jun 1989 |
JPX |
|
Parent Case Info
This application is a continuation of application Ser. No. 07/530,271, filed on May 30, 1990, now abandoned.
US Referenced Citations (9)
Foreign Referenced Citations (1)
Number |
Date |
Country |
170032 |
Apr 1956 |
JPX |
Continuations (1)
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Number |
Date |
Country |
Parent |
530271 |
May 1990 |
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