Calculation of Temperature Uniformity of Laboratory High Temperature Electric Stove

Calculation of Temperature Uniformity of Laboratory High Temperature Electric Stove
The arithmetic mean of the difference between the highest and lowest temperatures measured in each measurement is as follows:
In the formula: Δ Tu - Temperature uniformity, ℃; N -- number of measurements; Timax - the highest temperature measured at the i-th calibration point, ℃; Tim in - the lowest temperature measured at the i-th calibration point, ℃.
(5) Issues to be noted during the overall calibration process of the system
① The installation and wiring of standard thermocouples are carried out when the resistance furnace is powered off. After checking the wiring is correct, the resistance furnace can be started for heating.
② The measuring end of the standard thermocouple should be placed near the sample analysis location, but should not touch the sample or furnace wall to prevent contamination or damage to the standard thermocouple.
③ After reaching the temperature control point, in order to make the furnace temperature uniform and stable, it is necessary to control the temperature for 30 minutes before taking a reading. Due to the asynchronous display between the secondary instrument of the resistance furnace and the millivolt meter, the highest and lowest values of the millivolt meter should be read during each round of reading, and the corresponding highest and lowest values displayed by the secondary instrument should be read.
④ The measurement of furnace temperature uniformity must be carried out when it reaches thermal stability under no-load conditions. For resistance furnaces with fans, the fans should work normally during the measurement period.
⑤ If the reading error is too large, it is necessary to check whether the furnace is working properly. For example, to prevent the stainless steel protection tube of the control instrument thermocouple from being short circuited with the furnace wire, an insulating ceramic tube is added to the control instrument thermocouple. This requires cutting the insulating ceramic tube short to prevent the actual exposed length of the control instrument thermocouple from being 8-10 times shorter than the thermocouple protection tube; The sealing of the holes for inserting control instrument thermocouples on the furnace wall should be tight to prevent heat loss in nearby areas. In practice, taking certain measures can reduce the on-site correction value of furnace temperature with large indication error values.
⑥ After calibration, in order to avoid damaging the thermocouple or shortening its lifespan, it is not possible to quickly remove the standard thermocouple or open the furnace door because rapid cooling and heating can damage the furnace. Calculation of Temperature Uniformity of Laboratory High Temperature Electric Stove
The arithmetic mean of the difference between the highest and lowest temperatures measured in each measurement is as follows:
In the formula: Δ Tu - Temperature uniformity, ℃; N -- number of measurements; Timax - the highest temperature measured at the i-th calibration point, ℃; Tim in - the lowest temperature measured at the i-th calibration point, ℃.
(5) Issues to be noted during the overall calibration process of the system
① The installation and wiring of standard thermocouples are carried out when the resistance furnace is powered off. After checking the wiring is correct, the resistance furnace can be started for heating.
② The measuring end of the standard thermocouple should be placed near the sample analysis location, but should not touch the sample or furnace wall to prevent contamination or damage to the standard thermocouple.

④ The measurement of furnace temperature uniformity must be carried out when it reaches thermal stability under no-load conditions. For resistance furnaces with fans, the fans should work normally during the measurement period.
⑤ If the reading error is too large, it is necessary to check whether the furnace is working properly. For example, to prevent the stainless steel protection tube of the control instrument thermocouple from being short circuited with the furnace wire, an insulating ceramic tube is added to the control instrument thermocouple. This requires cutting the insulating ceramic tube short to prevent the actual exposed length of the control instrument thermocouple from being 8-10 times shorter than the thermocouple protection tube; The sealing of the holes for inserting control instrument thermocouples on the furnace wall should be tight to prevent heat loss in nearby areas. In practice, taking certain measures can reduce the on-site correction value of furnace temperature with large indication error values.
⑥ After calibration, in order to avoid damaging the thermocouple or shortening its lifespan, it is not possible to quickly remove the standard thermocouple or open the furnace door because rapid cooling and heating can damage the furnace.