Title :
Improved vacuum thermocouples
Author :
Levinson, H. ; Inglis, B.D. ; Kinard, J.R. ; Stollery, D.E.
Author_Institution :
Best Technol. Inc., Seattle, WA, USA
fDate :
June 27 1994-July 1 1994
Abstract :
Prior construction of single junction vacuum thermal convertors (SJTCs) did not consistently produce units with AC-DC differences of a few ppm or less. Four improvement modes have been introduced. (1) Elimination of flaming during the making of the mounting bead. (2) Changing of the feed-through posts from Dumet to platinum-iridium. (3) Decrease of the Thomson coefficient by changing from nickel-chromium to Evanohm heater wire. (4) Lowering of the temperature gradient along the heater wire in the vicinity of the thermocouple. SJTCs can now be constructed with AC-DC differences of less than 0.3 ppm at a high yield.<>
Keywords :
Peltier effect; chromium alloys; iridium alloys; measurement standards; nickel alloys; platinum alloys; thermocouples; units (measurement); AC-DC differences; Dumet; Evanohm; Ni-Cr; Pt-Ir; Thomson coefficient; feed-through posts; flaming; heater wire; mounting bead; nickel-chromium; platinum-iridium; temperature gradient; vacuum thermocouples; Australia; Converters; Laboratories; Manufacturing processes; Physics; Production; Temperature; Testing; Welding; Wire;
Conference_Titel :
Precision Electromagnetic Measurements, 1994. Digest., 1994 Conference on
Conference_Location :
Boulder, CO, USA
Print_ISBN :
0-7803-1984-2
DOI :
10.1109/CPEM.1994.333359
