Common faults and solutions of corundum tube furnace

　　The common faults and solutions of corundum tube furnace are as follows: 1. Corundum tube fracture reason: Poor thermal shock resistance: Corundum material is not resistant to rapid cooling and heating, and a large temperature difference can easily lead to fracture. Improper operation: The heating and cooling rate is too fast (exceeding 5 ℃/min). Directly cool naturally to room temperature at high temperatures. High temperature sample delivery/sampling or low-temperature objects touching high-temperature furnace tubes. Installation issues: There are no brackets on both sides of the furnace tube, causing deformation and fracture due to gravity. The flange did not use a support frame, and vertical stress caused fracture. Gas and impurities: Excessive airflow leads to large temperature differences. Residual samples or impurities inside the furnace tube (such as metal debris, substances containing K ₂ O/Na ₂ O/CaO/SiO ₂). Moisture and corrosion: New furnace tubes or those that have not been used or baked for a long time (need to be baked at 300-400 ℃ for 5-6 hours). Introduce corrosive gases such as sulfides and chlorides. resolvent: Control the heating and cooling rate: Heating rate ≤ 10 ℃/min, cooling rate ≤ 15 ℃/min, recommended 5 ℃/min. Set a cooling curve to avoid direct natural cooling. Standardized operation: The temperature during layout/sampling is ≤ 140 ℃. Avoid touching high-temperature furnace tubes with low-temperature objects. Optimize installation: Brackets are added on both sides of the furnace tube, and flanges are supported by brackets. Place insulation plugs (2 at each end, a total of 4) inside the furnace tube to form a balanced temperature field. Cleaning and maintenance: Regularly clean the inner wall of the furnace tube to avoid residual samples. New furnace tubes or those that have not been used for a long time need to be baked to remove moisture. Gas control: Gas flow rate ≤ 200SCCM (or 200ml/min), avoid cold air flow impact. Prohibit the introduction of corrosive gases. 2. Abnormal temperature control reason: Set problem: Set the temperature too low or too high. The temperature rise and fall rate setting is unreasonable. Component malfunction: Heating element damage (such as breakage). The thermocouple or temperature controller is damaged. Electrical connection: The connection point of the heating element is loose or short circuited. The fuse is blown or the fuse is damaged. resolvent: Check the set parameters: Adjust the set temperature to a reasonable range. Redesign the temperature rise and fall curve to ensure that the speed meets the requirements. Replace faulty components: Replace the broken heating element. Replace damaged thermocouples or temperature controllers. Check electrical connections: Tighten the connection point of the heating element and eliminate the short circuit. Replace the blown fuse or fuse. 3. Abnormal atmosphere control reason: Gas leakage: The flange seal is not tight or the O-ring is aging. The gas cylinder is not equipped with a pressure reducing valve or the pressure reducing valve is malfunctioning. Abnormal air pressure: The pressure gauge reading is abnormal (such as>0.02MPa). Improper closure of exhaust/intake valves. Gas flow rate: Excessive flow leads to unstable temperature field. resolvent: Check the sealing: Replace the aging O-ring or reinstall the flange. Ensure that the gas cylinder is equipped with a pressure reducing valve (range 0.01MPa-0.1MPa). Monitoring air pressure: Always pay attention to the pressure gauge, and if it exceeds 0.02MPa, immediately open the relief valve. Avoid closing the exhaust/intake valve to heat the sample. Control traffic: Limit gas flow rate to ≤ 200SCCM (or 200ml/min). 4. Electrical system malfunction reason: Power issue: The plug is not properly plugged in or the power is off. The fuse is blown or the control circuit fuse is damaged. Abnormal instrument display: The instrument has no power display or abnormal output. The set temperature does not match the temperature inside the furnace. resolvent: Check the power supply: Plug in the plug or connect the wire. Replace the fuse or fuse. Calibration instrument: Replace the damaged temperature sensor or temperature controller. Adjust the temperature measurement point position to ensure consistency with the layout point. 5. Vacuum system malfunction reason: Insufficient vacuum degree: Insufficient oil line in the vacuum pump or air leakage in the vacuum system. Electric butterfly valve has slow response or excessive diameter. Internal structural leakage: Abnormal water leakage caused by damage to the internal pipelines and interlayers of the furnace body. resolvent: Maintain the vacuum system: Check the mechanical pump oil line to ensure it is above the marked line. Replace the electric butterfly valve with an electric ball valve that responds slowly or has a large diameter. Check the internal structure: Inspect the airtightness of the furnace body section by section, repair or replace damaged parts.