The symptoms of thermocouple failure
Thermocouples are one of the most common means of measuring temperature. They are very hard, durable and accurate. However, even they can be damaged. Thermocouples rely on the effect that metals produce at different temperatures. The effect ratio of this reaction is directly proportional to the temperature difference of each metal. Why the thermocouple breaks depends on several factors, which we will discuss below.
2) abrasion and rupture
Engineers make thermocouples with metals. If they are exposed to wear and tear, they will eventually fail. The failure of the thermocouple is not obvious and the people who use it do not always notice that the metal is deteriorating and the sensor suddenly disappears. With some applications, a sudden failure can lead to a larger failure. As thermocouples get thinner, they tend to give inaccurate temperature readings, usually readings lower than the actual temperature. Changing thermocouples when they are at operating temperature is dangerous and challenging. As a result, in this case, the change in ambient temperature is one of the factors that should be considered by users and manufacturers.
2) impurities
If the thermocouple has impurities inside during its manufacture or installation, the deterioration of the thermocouple will occur more quickly. Its exposure to the atmosphere causes oxidation on the surface and this causes the currents carried to decrease at some point.
2) Reduce Symbo Voltage Effect
Thermocouple failure often begins with a decrease in the Sibak voltage effect, which occurs over several weeks and is not easily identified. Sibek voltage effect is the direct conversion of temperature difference into electrical effect. If the effect of the shunt voltage is low, the measured temperature will also be low. The actual temperature of the process is increased to create the required effect of the Sibak voltage. This causes excessive temperature production, and as a result, the materials are damaged by the increase in heat and disrupts the work process. p>
2) Weak pimples
When welders weld metal for thermocouples, a poor weld can cause an open junction. An open thermocouple check – which is a break in the thermocouple's hot junction – can detect this open junction. Because this bug is so easy to spot, it's unfortunate that this uniform mode of failure is common.
2) Changing the nature of the chemical
Again, this is a type of thermocouple failure that occurs when the chemical nature of one of the wires changes, resulting in a wrong thermocouple reading that appears to be correct. Usually due to excessive temperature, atmospheric particles enter and cause wrong reading of the thermocouple. In addition to high temperature, too much manipulation of the wire will lead to wrong reading if it is damaged.
2) Excessive heat
If the welding process is done incorrectly, it can increase the possibility of thermocouple failure. Overheating with a welding tool can destroy the wire. In addition, gas and atmosphere near the wire can enter the metal and change its properties. For this reason, expensive equipment produces thermocouples in a way that guarantees uniformity.
