Vacuum tube furnace

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Vacuum tube furnace: mainly used in metallurgy, glass, lithium anode and cathode materials, ceramics, new energy, LED light-emitting materials, abrasives and other industries, materials under certain atmosphere heating professional equipment.

vacuum tube furnace operation requirements :

1. Design rise and fall temperature curve:
In addition to the needs of the experiment, the application range of the tubular furnace should also be considered.

When the furnace tube is corundum furnace tube: the rate of temperature rise and drop in each temperature zone should not be too fast (≤ 5 ℃). The maximum operating temperature can be over 1200 ℃;

When the furnace tube adopts quartz tube: heating rate ≤ 10 ℃, cooling rate ≤ 15 ℃. The maximum temperature shall not exceed 1100 ℃;

When the silicon molybdenum rod is used as the heating element, it should not be used in the temperature range of 400 ℃ to 700 ℃ for a long time. Otherwise, the silicon molybdenum rod will be oxidized at low temperature, which will damage the element;

The maximum use temperature shall not exceed the allowable maximum heating temperature of the vacuum tube furnace, and the use time at the maximum heating temperature shall not be too long, not more than 1 hour;

2. When the tubular vacuum furnace is used for the first time or idle for a long time, it shall be pre baked, i.e. baking for 1 hour at 120 ℃ or 2 hours at 300 ℃ to avoid furnace damage.

3. Push the sample boat into the middle of the rigid and tube furnace as close to the middle as possible.

4. Plug insulation plugs at both ends to reduce heat radiation loss.

5. Install the gas furnace flange and confirm that the gasket falls into the groove.

6. Operation steps of sintering gas:
Close the working gas circuit and connect the gas outlet end of the tubular furnace to the vacuum pump.

Open the power supply of the vacuum pump, open the outlet valve, and empty the pipe body and the gas pipeline.

When the vacuum gauge of tubular furnace reaches – 0.1 (when the pointer reaches the end), close the air inlet valve. When the vacuum gauge of the tubular furnace does not move for an hour, it is still – 0.1, indicating that the tubular furnace has good sealing performance, otherwise, it is necessary to find out the leakage point and correct it.

Inert gas pressurization can also be used to test the air tightness, and the pressurization is generally not more than 0.05Mpa.

Turn the knob to open the main valve of the gas cylinder and slowly open the outlet pressure reducing valve to make the outlet air pressure within a reasonable range. (scope of application on pressure gauge).

Slowly open the inlet valve of the tubular furnace; at the same time, pay attention to the pressure gauge of the tubular furnace, and confirm that the air pressure is below 0.05Mpa (if the air pressure is higher than 0.05Mpa, use the outlet valve of the tubular furnace to vent).

When the air pressure of the tubular furnace is stable, close the inlet valve of the tubular furnace, open the outlet valve, vacuumize to – 0.1, and close the outlet valve of the tubular furnace.

After three times of air extraction, close the inlet valve and outlet valve, and connect the outlet hole to the conical bottle.

Open the air inlet valve of the tubular furnace and blow out the air valve to make the bubble in the conical flask appear at a speed of 2 / s. The discharged gas shall be discharged to the outdoor or exhaust cabinet.

Ventilate for ten minutes before heating.

Special reminder:

When using flammable and explosive gases such as hydrogen, it is necessary to check the leakage of equipment and gas transmission pipe, and then use a test tube to collect the exhaust gas for explosion test, and then heat it after confirmation.

If the oxygen cylinder is used, oil contamination is strictly prohibited. Pay attention that the gas pipeline and equipment are free of oil contamination, and the oil contamination is easy to explode in the high-pressure oxygen environment.

If acetylene is used, copper gas pipeline cannot be used, otherwise, the gas pipeline will produce acetylene copper, which is very easy to explode.

Pay attention to the amount of residual gas in the gas cylinder to ensure that there is no danger due to gas exhaustion during the experiment. The flammable gas shall be kept at a pressure of 0.2MPa after the experiment.

Open and close the air pressure valve slowly, do not use too much force.

7) The connection of power supply shall be carried out without load, i.e. the power supply shall be turned on first, and then the heating curve shall be set for heating. When the vacuum furnace is turned off, the heating button shall be turned off first, and then the power supply shall be cut off. The sequence of reclaiming is: cool to room temperature, turn off the power supply, confirm to turn off the gas bottle, and finally reclaim.

vacuum tube furnace precautions :

If the tube furnace uses the silicon carbon rod as the heating element, the resistance will gradually increase after a long time of operation, this phenomenon is called “aging”. If the temperature display value is inconsistent with the value given by the program or the swing is too large at 300 ℃ during the operation of tubular furnace, and the control deviation still exists, the manufacturer shall be contacted to recalibrate the tubular furnace.

Do not heat inflammable and explosive materials without professional training. Do not heat the mixed inflammable and explosive materials, or heat the products as inflammable and explosive materials.

The cooling process prevents the water in the conical bottle from being sucked back. At this time, the air output of the air outlet tank can be slightly increased.

After heating, wait until it cools to room temperature, then close the air inlet valve, and then take materials, especially reducing materials such as nano micron aluminum powder and magnesium powder. There is a risk of explosion when taking materials at high temperature (above 100 ℃). If necessary, after heating in flammable atmosphere, wash the chamber with inert gas or compressed air before taking materials.

When the air inlet and outlet of the air inlet valve are closed at the same time, the gas pressure in the pipe will increase under high temperature, causing explosion.

Please pay close attention to the pressure gauge of tubular furnace. Recommended value of safety pressure in pipe: – 0.05Mpa to 0.05Mpa.
The outlet of the tubular furnace shall be discharged to the outside or through the explosion-proof exhaust cabinet.