Precautions for using a vertical graphite carbon tube vacuum furnace

10-17-2025       Author: KJ technology

When using a vertical graphite carbon tube vacuum furnace, strict control should be taken from five aspects: operation specifications, safety protection, equipment maintenance, environmental control, and emergency response. The following are specific precautions:

1. Operating standards

Parameter Settings

Temperature control: Set the heating rate according to the material characteristics (such as ceramic sintering requiring slow heating to 1200-1600 ℃) to avoid cracking caused by thermal stress.

Vacuum degree adjustment: Before sintering, the vacuum degree inside the furnace needs to be pumped to the target value to prevent material oxidation; Accurate control of gas flow is required during inert atmosphere sintering.

Insulation time: Set the insulation time according to the thickness and density of the material (such as 2-4 hours for hard alloys) to ensure uniform performance of the sintered body.

Loading and unloading

Uniform distribution: Materials should be evenly placed in the furnace to avoid local overheating or uneven temperature.

Handle with care: Use specialized tools (such as graphite fixtures) for loading and unloading materials to prevent collision damage to the furnace body or heating elements.

Preheating treatment: Materials containing volatile components (such as certain polymers) need to be dried in advance to reduce gas release during the sintering process.

program control

Segmented heating: Adopting a multi-stage heating program (such as room temperature → 300 ℃ insulation for 1 hour → 800 ℃ insulation for 2 hours → target temperature) to meet the phase transition requirements of different materials.

Data recording: Record temperature, vacuum degree, gas flow rate and other parameters throughout the process for easy traceability and analysis.

2. Security protection

high-temperature protection

Insulation measures: Wear high-temperature gloves, protective face shields, and insulation clothing during operation to avoid direct contact with the surface of the furnace body (temperature can reach 2300 ℃ or above).

Warning signs: Set up high temperature warning signs around the furnace body and prohibit unrelated personnel from approaching.

Vacuum safety

Pressure monitoring: Real time monitoring of furnace pressure to prevent sudden pressure rise caused by vacuum pump failure.

Pressure relief device: Ensure the normal operation of the pressure relief valve and safety valve to avoid damage to the furnace due to overpressure.

Electrical safety

Grounding protection: Check if the equipment is properly grounded to prevent electric leakage and shock.

Insulation testing: Regularly test the insulation performance of heating elements and power lines to ensure no damage or aging.

Gas safety

Ventilation system: The operating room should be equipped with a forced exhaust device to prevent inert gas (such as argon) leakage and suffocation.

Gas purity: Use high-purity gas (such as 99.999% argon) to avoid impurities affecting sintering quality.

3. Equipment maintenance

routine inspection

Heating element: Check the appearance of graphite carbon tubes weekly for cracks, oxidation, or detachment.

Vacuum system: Check the oil level and quality of the vacuum pump daily, and replace contaminated oil in a timely manner.

Sealing components: Check the sealing rings of the furnace door and observation window every month for any signs of aging or deformation.

regular maintenance

Cleaning the furnace: After each batch of sintering, wipe the inner wall of the furnace with a dust-free cloth to remove any residue.

Calibration instruments: Calibrate temperature sensors and vacuum gauges quarterly to ensure measurement accuracy.

Lubricating components: Apply high-temperature lubricating grease to the lifting mechanism and transmission components to reduce wear.

Professional Repair

Fault handling: If abnormal heating or vacuum leakage is found, immediately stop the machine and contact professional personnel for repair.

Spare parts reserve: Reserve commonly used spare parts (such as graphite carbon tubes, sealing rings) to shorten maintenance cycles.

4. Environmental control

Temperature and humidity

Operating room temperature: Control between 5-35 ℃ to avoid extreme temperatures affecting equipment performance.

Humidity control: Relative humidity ≤ 70% to prevent electrical components from being affected by moisture and short circuiting.

cleanliness

Dust prevention measures: Dust resistant carpets are laid on the floor of the operating room, and dust covers are installed around the equipment.

Regular cleaning: Clean the operating room daily to reduce dust accumulation.

Ventilation requirements

Exhaust system: Ensure that the exhaust volume is ≥ 300m ³/h and promptly discharge trace gases generated during the sintering process.

5. Emergency response

Temperature out of control

Immediate shutdown: Press the emergency stop button to cut off the power supply.

Natural cooling: Open the furnace door to naturally cool down, and do not use water or force air cooling.

Vacuum leakage

Turn off the gas source: Quickly close the intake valve to prevent continuous gas leakage.

Personnel evacuation: If the leaked gas is toxic or flammable, immediately evacuate personnel and activate emergency plans.

electrical fault

Power off inspection: After cutting off the power, check whether the circuit and switch are short circuited or burned out.

Professional maintenance: Contact an electrician for troubleshooting and prohibit non professionals from operating.