Thermogravimetric AnalyzerThe key steps for daily maintenance and calibration are as follows:
1、 Daily maintenance: prevent malfunctions and extend lifespan
environmental control
Dry and ventilated: The instrument should be placed in a dry and ventilated room to avoid moisture and oxidation. The environmental humidity should be below 80%, and the temperature should be controlled between 18 ℃ and 30 ℃ to prevent the surface of the instrument from being exposed to strong light or prolonged sunlight.
Dust and moisture prevention: When idle for a long time, the power should be unplugged and the instrument should be covered with a dust cover to prevent dust or humid air from entering. Regularly clean the surface of the instrument with a dry cloth or soft brush to prevent dust accumulation from affecting heat dissipation and accuracy.
Component cleaning and lubrication
Sample tray and balance arm: Clean the sample tray after each experiment to prevent residue contamination. If the balance arm sticks to the sample, it can be subjected to high-temperature air burning (such as heating to 800 ℃) in the absence of the sample, burning off the residue, and then cooling down to check the cleanliness.
Lubrication of mechanical components: Regularly clean the jaws, sliding surfaces, and dovetail grooves, and apply a thin layer of MoS ₂ (molybdenum disulfide) grease to reduce wear. Check the sprocket transmission and screw fastening to prevent looseness from causing oil leakage or decreased accuracy.
Gas and Circuit Inspection
Gas flow calibration: Regularly calibrate the gas flow rate using a flow meter to ensure the purity and flow rate stability of the required atmosphere (such as nitrogen) for the experiment. Check whether the air circuit is leaking or blocked to avoid affecting the test results.
Circuit connection maintenance: Regularly check whether the connection wires on the back panel of the controller are loose to ensure stable power supply voltage (220V ± 20V, 50Hz ± 1Hz). When plugging in or unplugging interfaces, the power should be turned off to prevent equipment damage.
Battery and Hydraulic System Maintenance
Battery status monitoring: Regularly check the battery level and service life, replace aging batteries in a timely manner, and avoid instrument shutdown or data loss due to insufficient power.
Hydraulic system maintenance: Check the host and instruments for oil leakage, regularly replace sealing rings, combination gaskets, oil suction filters, and hydraulic oil to ensure the normal operation of the hydraulic system.
2、 Regular calibration: ensuring data accuracy
temperature calibration
Standard substance method: Using metals with known melting points (such as aluminum and nickel) or standard reference materials (such as calcium oxalate), stabilize the furnace temperature at a temperature close to 5-10 ℃ before the melting point, record the thermal effect and compare it with literature values, adjust the temperature controller until the measured value is consistent with the standard value.
Curie point method: Using the Curie temperature of ferromagnetic materials (such as nickel, which has a Curie point of 631 ℃), the temperature calibration point is determined by the inflection point of the mass change under the action of a magnetic field.
Hanging wire melting method: Hang a metal wire with an accurate melting point (such as indium, melting point 156.6 ℃) near the sample. When the temperature rises to the melting point, the metal wire melts, and the temperature is calibrated through a mass transition point.
Quality calibration
Standard weight method: After cleaning and preheating the balance, calibrate it using F1 grade stainless steel weights with nominal values of 1mg, 10mg, and 20mg to ensure accurate readings.
Blank test method: Run a blank test in the absence of samples to check the stability and repeatability of the balance. If the reading deviation is large, adjust the zero point or sensitivity of the balance until it stabilizes.
Baseline stability confirmation
Smooth line test: The normal baseline should be a smooth line without noise or offset during the heating process. If the baseline fluctuation exceeds the background value range, it may be caused by contamination of the balance arm, unstable gas flow, or malfunction of the optical sensing device, and should be promptly investigated and calibrated.
3、 Additional suggestions for extending lifespan
Avoid extreme conditions: When the test temperature exceeds 500 ℃, replace the aluminum crucible with a ceramic crucible; Using at temperatures above 800 ℃ will shorten the lifespan of the furnace; When using platinum plates above 1300 ℃, a small amount of aluminum oxide powder should be placed on the sample and reference plates to prevent adhesion.
Sample pretreatment: Strong acid and alkali samples need to be diluted and tested; The liquid level of the liquid sample should not exceed 1/2 of the crucible, and the solid powder should be less than 1/3 of the crucible; Ensure that the sample does not react with the crucible.
Long term idle handling: If the instrument is not used for a long time, the controller and computer should be turned off, and the transfer switch should be placed in the "load" position to avoid the electromagnetic reversing valve from being affected for a long time.