从冰点到液氮温度的宽低温区内,对随机选取的铜-康铜热电偶进行了重复性精度标定.测试结果表明,多次断偶重复焊接行为将产生约0.272mV的标准差.这意味着在液氮条件下,温度测量过程的最大误差将达8.98℃.所以,对现场、尤其对深冷区的现场进行精确测温实验中出现的断偶故障,重新焊接后必须重新标定才能继续使用.
On the freezing point to liquid nitrogen temperature range, repeatedly calibrating the Cu-CuNi thermocouple which is randomly selected. The result showed that the afresh welded Cu-CuNi thermocouple produced the standard deviation of electric potential reach 0. 272 mV. That means, in the lower temperature, the broken thermocouple is afresh welded, which caused the error of temperature would reach 8.98 ℃. Therefore, once happen to break off in the experiment of measuring temperature in deep cold zone, the thermocouple must be anew calibrated before using it over again.