Due to the limited conditions, the temperature correction of high-temperature furnace is very troublesome, many small factories do not have the conditions and ability to correct high-temperature furnace. However, according to the melting point of NaOH (318.3 ℃) and anhydrous Na2CO3 (851 ℃), it is also a simple and good method to correct the furnace temperature at 320 ℃ and 850 ℃. The specific correction method is as follows:
1. Cut off the power supply and slowly lower the temperature of the high temperature furnace to the room temperature. Observe whether the temperature displayed by the temperature controller is consistent with the room temperature. If not, adjust the zero knob on the temperature controller to make the temperature displayed by the temperature controller consistent with the room temperature.
2. Set the temperature pointer on the temperature controller to 320 ℃, Turn on the power supply, when the furnace temperature rises to 300 ℃, take a clean 20-25ml porcelain crucible, add 2-3gnaoh, place it in the center of the furnace of the high temperature furnace (the porcelain crucible should be 1-2cm high), and at 320 ℃, keep the constant temperature for 3-4min, take out the porcelain crucible, and observe whether the NaOH in it starts to melt. If it has started to melt, it means that the furnace temperature is consistent with the temperature displayed by the temperature controller. If NaOH has not started to melt, it means that the temperature of high-temperature furnace is lower than the display temperature of temperature controller. At this time, turn the zero adjustment knob of temperature controller to make its display temperature lower than 320 ℃ (gradually reduce by 5-10 ℃), and continue to raise the temperature to 320 ℃, Then put the porcelain crucible containing NaOH into the high temperature furnace, keep the temperature for 3-4min, take out the porcelain crucible. If the NaOH in the crucible has started to melt, it means that the temperature displayed by the controller is consistent with the furnace temperature of the high temperature furnace, otherwise continue to adjust until the temperature displayed by the temperature controller is consistent with the furnace temperature.
3. Continue to raise the temperature to 850 ℃, take another clean 20-25ml porcelain crucible, add 3-4g anhydrous Na2CO3, and place it in the center of the high-temperature furnace furnace. The adjustment method is the same as above.
4. If the furnace temperature of the high temperature furnace is higher than the temperature displayed by the temperature controller, the zero position adjusting knob of the temperature controller can be gradually increased by stages until the temperature displayed by the temperature controller is consistent with the furnace temperature.
5. When calibrating the furnace temperature, make a mark at each calibration point for easy use.
In the process of furnace temperature correction, the heating speed should not be too fast. When adjusting the zero adjustment knob of the temperature controller, the temperature level should not be too high, generally divided into 5-10 ℃ level. Observe the melting state of NaOH and anhydrous Na2CO3 frequently to avoid that the temperature is too high to exceed its melting point, so that the correction temperature is not accurate. Through the simple correction of high temperature furnace temperature, it is found that the temperature changes little, which can meet the detection requirements. Therefore, many small factories adopt NaOH and anhydrous Na2CO3 according to their melting point, and the simple correction of high temperature furnace temperature is a feasible method.
On 2018-08-08 11:45:46
