How to operate a multi gradient experimental tube furnace?

The operation of a multi gradient experimental tube furnace requires a series of strict steps to ensure the safety and smooth progress of the experiment. The following is the operation guide for the multi gradient experimental tube furnace:

1. Preparation before operation
Instrument inspection: Confirm whether all components of the tube furnace are intact, whether the instrument display status is normal, and whether all valves are closed.
Sample preparation: Place the sample in a suitable container and ensure that it does not react with the furnace tube or produce harmful volatiles.
Environmental preparation: Ensure that the surrounding environment of the tube furnace is clean, away from flammable and explosive materials, and maintain good ventilation.

2. Sample placement and gas path connection
Sample placement: Open the inlet flange and unscrew the three hexagonal screws evenly in multiple turns. Place the container containing the sample in the center of the furnace tube, ensuring that the center of the sample matches the section where the thermocouple is located. Then reinstall the intake end flange and tighten the screws.
Gas path connection: Connect the gas path in the order of the intake pipe, intake valve, exhaust valve, and safety bottle. It is usually advisable to use gas circuit switches and intake valves to regulate the gas flow rate, with a continuous bubble coming out of the safety bottle.

3. Vacuum pumping and inflation
Vacuum pumping: Close the inlet and outlet valves respectively, open the vacuum baffle valve, and then start the vacuum pump for pumping. Closely observe the pressure gauge at the intake end until its pointer indicates that the pipe has reached a vacuum state.
Inflation: After closing the vacuum pump and vacuum baffle valve, open the gas path in the order of the gas cylinder main valve, pressure divider valve, and pipeline switch, and inject the required gas into the furnace tube. When inflating, pay attention to the pressure gauge on the flange to ensure that the pressure inside the furnace tube does not exceed the specified value.

4. Temperature setting and heating
Temperature setting: Turn on the air switch and turn on the power. Set parameters such as starting temperature, target temperature, heating rate, and processing time in the temperature control system. For multi gradient experimental tube furnaces, it is also necessary to set temperature gradients in different temperature zones.
Heating start: Press the heating button to start heating. During the heating process, closely observe the display value of the temperature control system to ensure that the temperature inside the furnace rises and falls according to the set curve.

5. End of experiment and shutdown
Experiment End: When the experiment is over, turn off the heating button to stop heating the tube furnace. Wait for the furnace temperature to drop to a safe range (such as below 100 ℃) before stopping ventilation.
Shutdown operation: Close all valves and power switches, and disconnect the power connection. After the furnace has completely cooled down, open the furnace door and take out the sample.

6. Precautions
Safe grounding: The tube furnace must be properly grounded to ensure safe use.
Temperature control: Strictly control the furnace temperature and do not exceed its rated temperature. Avoid pouring liquids and dissolved metals into the furnace.
Heating rate: Set an appropriate heating rate based on the physical and chemical properties of the sintered material to prevent material spraying and furnace tube contamination.
Regular inspection: During use, the wiring condition of the electric furnace and its controller should be checked regularly to ensure good contact. At the same time, pay attention to whether the indicator is stuck or stuck.
Furnace tube protection: The furnace tube should avoid sudden temperature changes to prevent tube rupture. If the corundum tube is not used for a long time, it is recommended to bake it at around 300 ℃ to remove internal moisture.