The deterioration of the thermocouple is a quantitative process, and it is difficult to quantify it. It will vary with the type, diameter, operating temperature, atmosphere and time of the thermocouple.
Correct use of a thermocouple can prolong its life, so what problems should be paid attention to when using it, please take a look at the precautions:
Precautions for Using Thermocouples
1. Nominal pressure of thermocouple: generally refers to the static external pressure that the protection tube can withstand at working temperature and rupture.
2. Minimum insertion depth of thermocouple: should not be less than 8-10 times the outer diameter of its protective sleeve (except for special products)
3. Insulation resistance: When the ambient air temperature is 15-35°C, and the relative humidity is <80%, the insulation resistance is ≥5 megohms (voltage 100V). Thermocouple with splash-proof junction box, when the relative temperature is 93±3℃, the insulation resistance is ≥0.5 megohm (voltage 100V).
4. Insulation resistance at high temperature: At high temperature, the insulation resistance (per meter) between the thermocouple’s hot electrode (including double-branched type) and the protection tube and the double-branched hot electrode should be greater than the value specified in the table below.
Thermocouple is the most commonly used temperature sensor in scientific research and industrial production. Although its structure is simple, it will still cause large measurement errors if it is not used carefully.
