Long lasting thermocouple for high temperature measurements of liquid metals, mattes and slags

• US 5,232,286 A
• Filed: 04/10/1991
• Issued: 08/03/1993
• Est. Priority Date: 04/10/1991
• Status: Expired due to Fees

• Current Assignee: Her Majesty The Queen In Right of Canada As Represented By The Minister of National Defence
• Original Assignee: Her Majesty The Queen In Right of Canada As Represented By The Minister of National Defence
• Inventors: Skeaff, Jim, Dubreuil, Alain
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Bennett, G. Bradley
• Application Number:
  US07/682,947
• Time in Patent Office: 846 Days
• Field of Search: 374/139, 374/140, 374/163, 374/179, 374/180, 136/234, 136/236, 136/239, 136/240, 136/241, 75/235, 75/238, 75/245, 75/246, 75/247, 75/248
• US Class Current: 374/139
• CPC Class Codes: G01K 7/08 the object to be measured forming one of the thermoelectric materials, e.g. pointed type
• CPC Class Codes: H10N 10/82 Connection of interconnections
• CPC Class Codes: H10N 10/855 comprising compounds containing boron, carbon, oxygen or nitrogen

Abstract

A thermocouple is disclosed for the continuous measurement of the temperature of a molten phase, which thermocouple comprises two cermet elements of dissimilar metals in which the thermoelectric circuit is closed by the medium, the temperature of which is being measured. The use of dissimilar cermet elements as opposed to conventional metallic wires imparts to the thermocouple sensor a superior resistance to high temperature, corrosive environments which allows it to be used for extended periods of time and for varied applications. A method of using the thermocouple is also disclosed.

Claims

1. A thermocouple for the continuous measurement of the temperature of a molten phase, comprising:

first and second cermet elements for measuring the temperature of a molten phase, said first element being formed of a first cermet different from a second cermet of which the second element is formed, wherein a thermoelectric circuit of the thermocouple is closed by the molten phase.

2. A thermocouple as claimed in claim 1, wherein the thermocouple is adapted for incorporation into the refractory lining of a metallurgical reaction vessel so as to communicate with the molten phase contained within the interior of said reaction vessel.

3. A thermocouple as claimed in claim 2, wherein the metallurgical reaction vessel is a furnace, forehearth, ladle or converter or other means of containing a molten phase.

4. A thermocouple as claimed in claim 1, wherein the molten phase is a metal.

5. A thermocouple as claimed in claim 1, wherein the molten phase is a matte.

6. A thermocouple as claimed in claim 1, wherein the molten phase is a slag.

7. A thermocouple as claimed in claim 1, wherein the molten phase is a speiss.

8. A thermocouple as claimed in claim 1, wherein one element is a Mo-Al₂ O₃ cermet and the other element is a Cr-Al₂ O₃ cermet.

9. A thermocouple as claimed in claim 1, wherein one element is a Mo-ZrO₂ cermet and the other element is a Cr-Al₂ O₃ cermet.

10. A thermocouple as claimed in claim 1, wherein the dissimilar cermet elements are each composed of a different metal selected from the group consisting of Zr, Mo, Cr, Ti, V, Nb, Ta, W, Re, Ru, Rh, Co, Pt, Au, Os, Ag, Pd, U, La, Y, and Mn, and a ceramic selected from the group consisting of Al₂ O₃, ZrO₂, TiO₂, MgO, Y₂ O₃, La₂ O₃, Sc₂ O₃, SiC and B₄ C.

11. A method for continuous measurement of the temperature of a molten phase comprising:

incorporating into an interior refractory wall of a furnace or other vessel a thermocouple having first and second cermet elements, said first element being formed of a first cermet which is different from a second cermet of which the second element is formed, and

directly measuring the temperature of the molten phase contained in the furnace or other vessel with the cermet elements.

12. The method according to claim 11, wherein one end of each of the two cermet elements physically contacts the molten phase.

13. The method according to claim 12, further comprising:

connecting the other ends of each cermet element to a metallic thermocouple, wherein the metallic thermocouple is connected to a temperature readout meter.

14. The method according to claim 11, wherein the molten phase completes a thermoelectric circuit of the thermocouple.