How to correctly use the thermocouple temperature sensor

Four points needed for the thermocouple temperature sensor using the

1, the introduction of improper installation error:

such as the location of the thermocouple temperature sensor installation and insertion depth cannot reflect the reality of the furnace temperature, etc. , in other words, the thermocouple temperature sensor should not be in too close to the door and heating, the depth of the insert should be at least 8 ~ 10 times the diameter of the protection tube; Thermocouple temperature sensor to protect casing and the wall between the interval of missing overflow or cold air into the furnace heating insulation material, so the thermocouple protection tube and furnace wall temperature sensor hole the space between the application of refractory mortar or insulating material such as asbestos rope jam to avoid cold and hot air convection and affect the accuracy of temperature measurement; The cold end thermocouple temperature sensor is too close to the furnace temperature over 100 ℃; Thermocouple temperature sensor installation should as far as possible to avoid strong magnetic field and electric field, so should not be the thermocouple temperature sensor and power cable line in order to avoid interference caused by errors within the same catheter; Thermocouple temperature sensor cannot be installed in a few measured medium flowing area, when measured with a thermocouple temperature sensor tube gas temperature, must make the thermocouple temperature sensor installation against the flow direction, and fully contact with the gas.

2, the error of the insulation deterioration and introducing

such as thermocouple temperature sensor of the insulation, protection tube and wire plate too much dirt or salt slag between the thermocouple temperature sensor electrode and wall insulation fault, at high temperatures is more serious, which not only causes the thermoelectric potential loss but also can introduce interference, the resulting error sometimes can reach.

3, the error of thermal inertia is introduced into the

due to the thermal inertia of thermocouple temperature sensor instrument behind the change of the measured temperature, indicating value of this influence is particularly acute in rapid measurement. So should be used as thermal electrode is fine, protecting tube diameter smaller thermocouple temperature sensor. Temperature measuring environmental permits, even protecting tube can be taken. Due to measurement lags behind, with a thermocouple temperature sensor to detect the temperature fluctuations of the amplitude of the furnace temperature fluctuation amplitude is small. Measurement lags behind, the greater the fluctuation amplitude of the thermocouple temperature sensor is small, and the difference of the actual temperature. When the time constant of thermocouple temperature sensor with temperature or temperature control, instrument display temperature fluctuation is small, but the actual furnace temperature fluctuations can be quite large. In order to accurately measure temperature, should choose small time constant of thermocouple temperature sensor. Time constant is inversely proportional to the heat transfer coefficient and heat the thermocouple temperature sensor is directly proportional to the diameter, material density and specific heat, such as to reduce the time constant, in addition to the increased heat transfer coefficient, the most effective way is to try to decrease the size of the hot end. Use, usually USES the material with good thermal conductivity, thin, small diameter of the tube wall to protect casing. In the precision of temperature measurement, using unprotected casing bare wire thermocouple temperature sensor, but the thermocouple temperature sensor is easy to damage, should timely correction and replacement.

4, thermal resistance error

at high temperature, such as protecting tube with a layer of ash, dust attached to the above, the thermal resistance increase, hinder the heat conduction, when the temperature is lower than the true value of measured temperature value. Therefore, we should maintain the cleanness of thermocouple temperature sensor protection tube outside, to reduce the error.