Vertical tube furnaceAs a core equipment in high-temperature experiments and industrial production, its lifespan and operational stability are directly affected by maintenance quality. Starting from the equipment structure and operating scenarios, summarize the key maintenance measures as follows:
1、 Daily inspection and cleaning
Furnace and tube cleaning
Physical cleaning: After each experiment, use a vacuum cleaner or compressed air to remove residual powder from the furnace tube to avoid high-temperature carbonization and corrosion of the furnace tube.
Chemical cleaning: For carbon deposition, soak the furnace tube in 10% dilute hydrochloric acid for 2 hours and then rinse (ensuring compatibility of furnace tube materials, such as quartz tubes, avoiding strong acids).
Furnace inner wall: Use a soft bristled brush to remove residue and avoid damage caused by sharp tools scratching.
Sealing and airtightness inspection
Soap water method: Fill the furnace tube with 0.1MPa nitrogen gas every month, apply soap water to the interface, and observe the bubbles to determine leakage.
Vacuum degree test: Use a vacuum gauge every quarter to test the ultimate vacuum degree. If it is below 10 ⁻ ² Pa, check the sealing ring or vacuum pump.
Heating element inspection
Appearance inspection: Visually inspect the heating wire (silicon molybdenum rod/resistance wire) monthly for oxidation, fracture, or localized melting.
Replacement standard: If the diameter of the heating wire shrinks by more than 20% of its original size, or if the resistance value changes by more than ± 10%, it needs to be replaced immediately.
2、 Key component maintenance
Temperature control system calibration
Standard substance method: Use high-precision thermocouples (such as S-type) to calibrate the temperature measurement points inside the furnace every six months. If the error exceeds ± 5 ℃, adjust the PID parameters.
Program testing: Run a step heating program (such as increasing from 20 ℃/min to 1000 ℃), record the deviation between the actual temperature curve and the set value, and optimize the temperature control accuracy.
Vacuum pump maintenance
Oil change cycle: Replace the vacuum pump oil every 200 hours to avoid carbonization of the oil quality that may cause a decrease in pumping speed.
Air intake filtration: Install a filter screen at the inlet of the vacuum pump to intercept powder samples and prevent pump body wear.
Gas pipeline inspection
Flow calibration: Use soap bubble flowmeter to calibrate gas flowmeter every month, and adjust if the error exceeds ± 5%.
Pipeline aging: Check the gas pipeline for aging every quarter, with a focus on rubber hoses (it is recommended to use metal bellows).
3、 Safety and protective measures
Electrical system inspection
Wiring terminals: Tighten the wiring terminals between the heating element and the power supply every quarter to avoid poor contact and local overheating.
Insulation testing: Use a megohmmeter every six months to test the insulation resistance of the heating element to ground, which should be ≥ 10M Ω.
Line aging: Check if the power cord is damaged, with a focus on inspecting cables in high-temperature areas (such as behind the furnace).
Operating environment requirements
Environmental conditions: The equipment needs to be used indoors, with an ambient temperature of -10~40 ℃, an altitude not exceeding 1000 meters, and a relative humidity of ≤ 85% RH.
Safety protection: Explosion proof valves must be installed for flammable gases such as hydrogen, and heating is prohibited when the oxygen concentration exceeds 21%; The fixing of the furnace body requires quarterly inspection of whether the bracket is loose.
Emergency situation handling
Leakage/fire: Immediately press the emergency stop button, cut off the power, use a fire extinguisher to extinguish the initial fire, evacuate personnel, and call the fire alarm.
Overtemperature alarm: Confirm that the overtemperature alarm function is normal to avoid sample or equipment damage caused by temperature control failure.
4、 Long term maintenance and recording
Regular major repairs
Annual maintenance: Conduct a comprehensive maintenance every year, including replacing sealing rings, cleaning thermocouples, inspecting furnace structure, etc.
Lubrication maintenance: Apply high-temperature lubricating grease (such as molybdenum disulfide) to the furnace door slide rail every six months.
Maintenance Record
Equipment file: Record the maintenance time, replacement of parts, and calibration data for easy traceability of issues.
Personnel training: Operators must pass the assessment of the "Safety Operation Regulations for Tube Furnaces" to avoid equipment damage caused by misoperation.
5、 Maintenance effectiveness and cost-effectiveness
Extended lifespan: Through system maintenance,Vertical tube furnaceThe lifespan can be extended to 8-10 years (the industry average lifespan is 5-6 years).
Cost reduction: Preventive maintenance costs only 1/5 of fault repairs, and can avoid data loss and experimental delays.
Priority sorting: Heating element inspection (core) → Furnace tube cleaning (high frequency) → Temperature calibration (accuracy guarantee) → Vacuum system (safety critical) → Mechanical and electrical (long-term stability).