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“熔线法”检定高温热电偶,其独特之处在于经济、简便、又有一定的准确性。前阶段我们曾经利用“熔线法”在铝、金、钯、铂四个熔钯点温度对W—5Re/W—20Re(批号7805—87)高温热电偶进行检定。并建立一条适合该批热电偶的“热电势——温度”关系方程式。本文增加了锌点参考温度,并用同亲的“熔线法”对不同批号及不同型号的钨—铼热电偶进行分度试验,并得到如下热电方程式E_t=a_0+a_1t+a_2t+a_3t~3+a_4t~4+…+a_nt~n。应用不同金的已知熔点,上述方程式常数项即可求得。因此,W-5Re/W-20 Re及W-3Re/W-25Re的方程式分别为:E_((5/20))=-2.322+2.432×10~(-2)t-7.807×10~(-6)t~2+3.291×10■t~3-6.718×10~(-13)t和E(■25))=-1.613+1.830×10~(-2)t+1.937×10~(-6)t~2-2.328×10■t~3-2.195×10■t~4。上述方程式计算结果和不同厂商的分度值在允许误差±1%t之内。因此,这样方法可以建议作为工作生产实际应用。
“Fuse method” test high temperature thermocouple, its uniqueness is economical, simple, there is a certain accuracy. In the previous stage, we used the “fusing method” to test the W-5Re / W-20Re (batch number 7805-87) high temperature thermocouple at the melting point of aluminum, gold, palladium and platinum. And establish a “thermopower-temperature” equation suitable for the batch of thermocouples. In this paper, the reference temperature of zinc point was added, and the indexing tests of different lot numbers and different types of tungsten-rhenium thermocouples were carried out by the same “fuse method”. The thermoelectric equations E_t = a_0 + a_1t + a_2t + a_3t ~ 3 + a_4t ~ 4 + ... + a_nt ~ n. Applying the known melting point of different gold, the constant terms above can be obtained. Therefore, the equations for W-5 Re / W-20 Re and W-3 Re / W-25 Re are: E _ ((5/20)) = -2.332 + 2.432 × 10 -2 t-7.807 × 10 ~ -6) t ~ 2 + 3.291 × 10 ■ t ~ 3-6.718 × 10 ~ (-13) t and E (■ 25)) = -1.613 + 1.830 × 10 -2 t + 1.937 × 10 ~ -6) t ~ 2-2.328 × 10 ■ t ~ 3-2.195 × 10 ■ t ~ 4. The above formula and the results of different vendors sub-degree of tolerance within ± 1% t. Therefore, such a method can be suggested as a practical application of work production.