Gb platinum rhodium thermocouple technical requirements

(1) Stability of platinum-rhodium thermocouple:

A: thermocouple composed of standard grade platinum-rhodium thermocouple wire, when the temperature of the reference end is ℃, when the temperature of the measurement end is 1084.88℃(copper point), the thermoelectric potential should be 11.640±0.035℃ mV.

B: When the thermocouple composed of even wire is used in 1600℃ air for 200 hours, the thermoelectric potential change measured at 1500℃ before and after use shall not exceed ±47μν(about 4℃).

(2) Platinum wire purity of platinum-rhodium thermocouple:

A: The purity of platinum wire in platinum-rhodium 10-platinum thermocouple wire is indicated by resistance ratio (R100/R0) : P100/R0>=1.3918.

R100 and RO are the resistance values of platinum wire at 100℃ and 0℃ respectively.

B: The purity of platinum wire in platinum-rhodium 13-platinum thermocouple wire is indicated by W(100℃), and W(100℃) of standard grade is >1.3920.

Note: W = R100 / Ro (100 ℃).

(3) Platinum-rhodium thermocouple surface quality:

Platinum-rhodium thermocouple wire surface should be flat, bright, no oil, no folding, no crack, no burr and interlayer, allow to have not more than the diameter tolerance of fine scratches and depressions and individual dark spots.

3, platinum-rhodium thermocouple in cleaning requirements are as follows:

Put the sample into 30-50%(volume ratio) hydrochloric acid or pin acid solution to boil for 15 minutes or soak for 1 hour, take out after boiling with distilled water several times, until removing the acid on the couple wire so far.