Common faults of lifting bell jar furnace

　　The common faults of the lifting bell jar furnace can be classified into five categories: electrical faults, mechanical faults, temperature control faults, atmosphere control faults, and sealing faults. The specific manifestations and solutions are as follows: 1. Electrical malfunction Power Problem Phenomenon: The device cannot start and there is no display on the touch screen. Reason: Poor contact of power cord, power switch not turned on, or blown fuse. Solution: Check the power cord connection, confirm the switch status, and replace the fuse. Heating element malfunction Phenomenon: There is no reaction or slow heating at the furnace temperature. Reason: Heating elements (such as silicon carbon rods, silicon molybdenum rods) are broken, aged, or internally short circuited. Solution: Replace broken or aged heating elements and check if the insulation layer is damaged. Controllable silicon fault Phenomenon: The device trips or burns out the fuse. Reason: thyristor breakdown or overload operation. Solution: Replace the thyristor components and check if the load exceeds the limit. 2. Mechanical malfunction Fault in lifting structure Phenomenon: The lifting kiln truck is not lifted in place or stuck. Reason: Overload of the lifting motor, improper or damaged position of the travel switch. Solution: Check the motor air circuit breaker thermal overload switch, adjust or replace the travel switch. Wear of transmission components Phenomenon: Abnormal noise or shaking occurs during the lifting process. Reason: Wear or insufficient lubrication of transmission components such as chains and gears. Solution: Replace worn parts and replenish lubricating oil. 3. Temperature control malfunction Excessive temperature fluctuations Phenomenon: The furnace temperature fluctuates and cannot be stabilized. Reason: Heating element aging, control system malfunction (such as improper PID parameter adjustment), or poor thermocouple contact. Solution: Replace the heating element, readjust the PID parameters, and check the thermocouple wiring. Over-temperature alarm Phenomenon: Touch screen displays over limit temperature trip protection. Reason: The extreme protection temperature setting in the system configuration is incorrect or the thermocouple is disconnected. Solution: Reset the limit protection temperature and check if the thermocouple is damaged. 4. Atmosphere control malfunction Unstable gas flow rate Phenomenon: The traffic fluctuates between high and low, or there is no display. Reason: Insufficient gas source pressure, malfunction of mass flow controller, or pipeline blockage. Solution: Check the air source pressure, replace the mass flow controller, and clear the pipeline. The atmosphere control fluctuates greatly Phenomenon: The composition of the atmosphere inside the furnace is unstable. Reason: Improper adjustment of PID parameters in the atmosphere controller or incorrect gas mixing ratio. Solution: Reset the PID parameters and adjust the gas mixing ratio. 5. Sealing failure Furnace body leakage Phenomenon: The pressure inside the furnace cannot be maintained, resulting in oxidation or pollution. Reason: Leakage of pipeline valves, aging of kiln car seals, or leakage of protective covers around the furnace body. Solution: Replace the leaking valve or sealing strip, and tighten the screws of the protective cover. Circulating fan leaks air Phenomenon: There is gas leakage at the fan. Reason: Severe wear of graphite packing or deformation of motor shaft. Solution: Replace the graphite packing or repair the motor shaft.