Small opening microVertical tube furnaceThe furnace tube diameter can be selected as φ 30/50mm, which is suitable for hanging and quenching samples in a vacuum or atmosphere protection environment. If different accessories and devices are used in combination, it can also be used as a fluidized bed vertical tube furnace, specifically for CVD experiments on powder surface deposition. At this time, a quartz sand core with a pore size of 5-15um is embedded inside the high-purity quartz furnace tube. The sintered powder is placed on a sand core layer, and gas is introduced from the flange at the lower end of the furnace tube. Through the sand core layer, the sample particles are suspended in the heating zone (usually stable in the constant temperature zone) under the drive of the airflow, and sedimentation experiments are carried out.
Key points of maintenance management:
Heating element maintenance:
Regular inspection: visually inspect the heating wire (silicon molybdenum rod/resistance wire) monthly for oxidation, breakage, or partial melting, and tighten the wiring terminals quarterly.
Replacement standard: If the diameter of the heating wire shrinks by more than 20% or the resistance value changes by more than ± 10%, it needs to be replaced immediately.
Extended lifespan: Oxidation losses can be reduced by adding an oxide layer or gas protection measures (such as nitrogen).
Furnace tube cleaning and airtightness:
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 corrosion.
Chemical cleaning: For carbon deposition, soak in 10% dilute hydrochloric acid for 2 hours (to confirm the compatibility of the furnace tube material).
Airtightness testing: Check for interface leaks using soap water method every month, and test the vacuum degree every quarter (if it is below 10 ⁻ Pa, the sealing ring needs to be replaced).
Safety protection and structural inspection:
Overtemperature protection: Ensure that the overtemperature alarm and power-off functions are functioning properly to avoid overheating and damage to the heating element.
Furnace body inspection: Regularly observe the cracks in the shell and the aging of the insulation layer to prevent safety accidents caused by high temperatures.
Vacuum and Atmosphere System Maintenance:
Vacuum pump maintenance: Regularly replace the vacuum pump oil, clean the pipeline, and avoid white sediment blockage.
Sealing ring replacement: Aging of the heat-resistant silicone ring can lead to insufficient vacuum degree and needs to be replaced in a timely manner.