Cautions for use of standard thermocouples 1. When using and storing, the porcelain tube and plastic tube on the thermocouple shall not be arbitrarily removed, the standard shall be kept to be straight, and the thermocouple shall not be seriously bent; the quartz outer tube shall be added; During storage, the standard thermocouple wrpb-2 shall be protected from severe mechanical shocks. The supervision and periodicity inspections shall be carried out periodically in accordance with the “Rules for the Measurement of Standard Platinum Rhodium 10-Platinum Thermocouples†(jjg75-95). .
Third, the verification certificate attached to the product should be properly preserved. The next time the inspection must be accompanied by the original verification certificate, no certificate will not be used as a standard thermocouple test.
Anhui Tiankang second standard thermocouple use method 1, before use, check whether the standard even number and the product number on the certificate is the same.
Second, when used, the standard couple can be measured by taking it out of the glass outer protective tube and putting it into the quartz outer protective tube. After use, re-inserted in the glass sheath to save.
Third, when the second-class standard thermocouple wrpb-2 produced by Anhui Tiankang is used for the verification of industrial thermocouples, the reference end of the standard couple and the thermocouple to be measured shall be at 0°C. The specific methods and procedures were carried out in accordance with the "Standard Platinum Rhodium 10-Platinum Thermocouple Verification Regulations" (jjg75-95) issued by the Quality and Technical Supervision Bureau.
Fourth, when using the standard even for precise temperature measurement, the temperature t is determined by the following formula: (When this formula is omitted) When measuring the temperature, a corresponding e(t)-t correspondence table should be prepared based on the approximate temperature range of the thermocouple. Then, the temperature t can be obtained according to the above-mentioned comparison table based on the measured thermoelectric value of the thermocouple. The temperature interval of the comparison table is set by the user.
Standard thermocouples are mainly used for testing, comparison, comparison, and general thermocouple work accuracy. For the standard thermocouple working principle, there are many friends who are not too familiar with it. Today we put the second-class standard thermocouple (wrpb-2). Introduce, the product standard mainly uses the national standard, the standard thermocouple divides into the first-class standard thermocouple and the second-class standard thermocouple two, the first-class standard thermocouple is the second highest thermocouple standard, second class standard Thermocouples are thermocouples with relatively high accuracy, good physical and chemical properties, and good oxidation resistance at high temperatures. The thermocouples of the standard thermocouples have excellent stability and reproducibility of linear thermocouples. Standard thermocouples are mainly used to test inexpensive metal thermocouples, precision temperature measurements, etc. The standard thermocouples (standard platinum rhodium thermocouples) have a detection cycle of one year.
Second-class standard thermocouples (second-class platinum é“‘ 10-platinum thermocouples) Main technical specifications Product model: wrpb-2
Product length: l=1000mm
Wire diameter: φ0.5mm
Detection range: 300°C~1300°C
Product index number: s-type second-class standard couple, thermoelectric value, requirements:
The thermoelectric potentials of the first and second standard thermocouples should be at copper (1084.62 °C), aluminum (660.323 °C) or tantalum (630.63 °C), and zinc (419.527 °C). When the reference junction temperature is 0 °C, the thermoelectric potential should be Meet the following requirements:
e(tcu)=(10.575±0.015)mv
e(tal)=5.860+0.37[e(tcu)-10.575]±0.005mv
e(tasb)=5.553+0.37[e(tcu)-10.575]±0.005mv
e(tzn)=3.447+0.18[e(tcu)-10.575]±0.005mv
Second, second standard thermocouple stability is determined by the change of the electromotive force of its copper point (the difference of the two thermoelectric potentials), and the newly manufactured second-class standard thermocouple is no more than 5uv. The second-class thermocouple copper thermopotential in use is used. The annual variation does not exceed 10uv.
Third, the standard thermocouples often used, in order to ensure accurate and reliable quantities, should be based on the use of necessary supervision and verification, the second standard thermocouple monitoring is a standard thermocouple or infrequent use of two Standard thermocouples are used as stan- dards. Their conformance is determined by the difference between the measured thermoelectric potential at the copper point and the thermoelectric potential given by the metrological verification certificate (the difference is not more than 7uv).
IV. The standard thermocouples that meet the national metrological verification procedures of the platinum-germanium 10-platinum thermocouples by the metrological verification of the jjg75-1995 standard are issued with the verification certificate. The valid figures for the second-class standard thermocouple thermo-electromotive force values ​​given in the certificate are three digits after the decimal point (see the following certificate data for details).
Fifth, the standard thermocouple test cycle is one year, standard thermocouple structure: the positive electrode is platinum rhodium wire, the negative electrode is platinum wire, the sleeve has a 550 mm long double-insulated ceramic tube; the reference terminal positive pole set of red or pink plastic tube, Negative set of white or blue plastic tubes; the entire product is stored in a glass sleeve.
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