Common faults and solutions for customized tube furnaces

Customized tube furnaces may encounter some common faults during use. Here are some common faults and their solutions:

1. Power and heating issues
Fault phenomenon: After the tube furnace is powered on, there is no power display on the instrument.
Possible reasons: The plug is not properly inserted, the fuse is blown, or the control circuit fuse is blown.
Solution: Check if the plug is properly inserted or connected, replace the fuse, or check for a short circuit before replacing the fuse.
Fault phenomenon: The power supply and heating elements of the tube furnace are normal, but the temperature inside the furnace does not rise.
Possible reasons: The set temperature is too low or the control circuit is damaged.
Solution: Adjust the set temperature to the desired range, or notify professional maintenance personnel to repair the control circuit.
Fault phenomenon: The ammeter has no current, but the voltmeter has voltage.
Possible cause: Heating element breakage.
Solution: Open the furnace door, observe the integrity of the heating element, and replace the broken heating element.

2. Temperature control issues
Fault phenomenon: The set temperature does not match the temperature inside the furnace, resulting in a positive or negative deviation.
Possible reasons: Damage to temperature sensor or temperature controller, or deviation between temperature measurement point and layout point.
Solution: Replace the temperature sensor or thermostat, or adjust the position of the temperature measurement point and the layout point to ensure accuracy.
Fault phenomenon: The tube furnace instrument is outputting normally, but the OUT indicator light is not flashing.
Possible cause: The main circuit has malfunctioned.
Solution: Check if the heating resistor wire is broken, if the thyristor is damaged, and replace the damaged components.

3. Instrument display issue
Fault phenomenon: The instrument SV alternately displays “ORAL”.
Possible cause: Short circuit of thermocouple.
Solution: Replace the thermocouple to restore the normal display of the instrument.
Fault phenomenon: The instrument SV alternately displays “HIAL”.
Possible reason: The temperature inside the furnace exceeded the limit, and the instrument acted as a protective measure.
Solution: After the temperature drops to a safe level, the instrument will automatically return to normal.

4. Other common questions
Furnace cracking:
Possible reason: Failure to preheat after first use or prolonged disuse.
Solution: After the first use or long-term disuse, heat the tube furnace to around 120 ℃ and bake for 1 hour, then heat it to around 300 ℃ and bake for 2 hours before use. At the same time, ensure that the furnace temperature does not exceed the rated temperature to avoid damaging the heating elements and furnace lining.
Decreased vacuum degree:
Possible reasons: Aging or damage of the heat-resistant silicone ring between the stainless steel flanges, or malfunction of the vacuum system.
Solution: Replace the heat-resistant silicone ring between the stainless steel flanges, reinstall the stainless steel flanges, or replace and repair the vacuum system to improve the overall vacuum degree of the tube furnace system.
Heating rate issue:
Possible reason: When using a cold furnace, the heating rate in the low-temperature section is too fast or there is a significant difference in heating rate between different temperature sections.
Solution: When setting the heating rate, the physical and chemical properties of the sintered material should be fully considered to avoid contamination of the furnace tube caused by spraying due to too fast a heating rate.

In summary, the common faults of customized tube furnaces mainly include power and heating issues, temperature control issues, instrument display issues, and other common problems. Corresponding solutions can be taken to troubleshoot and repair these faults. During the maintenance process, it is essential to follow safety operating procedures and ensure the stable operation of the equipment.