Precautions for using a vertical tube heat treatment electric furnace

As a high-temperature equipment, the vertical tube type heat treatment electric furnace is widely used in material heat treatment, coating, annealing and other processes. However, its high temperature, high voltage, electrical complexity and other characteristics also bring potential risks. To ensure the safe operation of the equipment, extend its service life, and achieve ideal processing results, the following precautions must be strictly followed during use:

1. Preparation before operation
environment check
Ensure that there are no flammable or explosive materials around the equipment, good ventilation, and avoid the accumulation of high-temperature gases or harmful substances.
Check if the ground is flat to prevent equipment from tilting and causing furnace tube rupture or material slippage.
Confirm that the equipment is well grounded to avoid the risk of electrical leakage.
Equipment inspection
Furnace body and furnace tube: Check whether the furnace body has cracks, deformation or corrosion, and whether the inner wall of the furnace tube is clean and free of impurities.
Sealing components: Check whether the sealing rings of furnace doors, flanges, observation windows and other parts are intact, and replace aging or damaged sealing components if necessary.
Electrical system: Check whether the power cord, plug, and socket are intact, without damage or exposed wires; Confirm that the grounding wire connection is reliable.
Control system: Check whether the temperature controller, pressure gauge, flow meter and other instruments are displaying normally, and whether the calibration error is within the allowable range.
Gas system: Check the pressure of gas cylinders, whether there are leaks in gas pipelines, whether valve switches are flexible, and whether accessories such as pressure reducing valves and filters are intact.
Material preparation
Select appropriate materials according to process requirements, ensure that the material size matches the inner diameter of the furnace tube, and avoid material jamming or blockage.
Clean the surface of materials, remove impurities such as oil stains and rust, and prevent the generation of harmful gases or contamination of furnace tubes at high temperatures.
For easily oxidizable materials, surface treatment (such as coating with a protective layer) or inert gas protection process should be selected in advance.

2. Operation process specification
temperature control
Heating rate: Strictly follow the heating rate set by the process curve to avoid excessive heating that may cause excessive thermal stress in the furnace tube or material cracking.
Insulation stage: After reaching the set temperature, maintain sufficient time to ensure uniform heating of the material and avoid temperature fluctuations exceeding ± 5 ℃.
Cooling control: Select appropriate cooling methods based on material characteristics (such as furnace cooling, temperature controlled cooling, or forced cooling) to prevent rapid cooling from deteriorating material properties or damaging furnace tubes.
atmosphere control
Vacuum environment: When vacuuming is required, first close the furnace door and check the sealing before starting the vacuum pump; After the vacuum degree meets the requirements, the reaction gas can be introduced.
Gas flow rate: Accurately control the gas flow rate according to process requirements to avoid excessive flow rate causing high furnace tube pressure or insufficient flow rate affecting reaction efficiency.
Gas replacement: Before introducing the reaction gas, inert gas (such as nitrogen) should be used to replace the air in the furnace multiple times to prevent oxidation or explosion risks.
Pressure monitoring
Real time observation of pressure gauge readings to ensure that the pressure inside the furnace is within a safe range (usually not exceeding 0.02 MPa).
If the pressure rises abnormally, immediately stop heating and check whether the gas pipeline and valves are blocked or leaking.
Material loading
Use specialized tools (such as high-temperature resistant fixtures) to load materials and avoid direct contact with high-temperature components by hand.
The materials should be evenly distributed inside the furnace tube to avoid local overheating or insufficient heating.
For long tubular materials, support frames should be used to fix them and prevent bending or deformation.

3. Safety protection measures
personal protection
Operators are required to wear personal protective equipment such as protective goggles, heat-resistant gloves, and heat-resistant clothing to prevent burns or splashes.
When operating in high temperature or high pressure environments, respiratory protective equipment (such as gas masks) should be worn to prevent inhalation of harmful gases.
Equipment protection
Set up protective barriers or warning signs around the furnace to prevent unrelated personnel from approaching.
Install insulation layers on high-temperature components such as furnace doors and flanges to reduce surface temperature and prevent burns.
emergency response
Develop emergency plans and clarify the procedures for handling unexpected situations such as fires, leaks, and power outages.
Equip emergency equipment such as fire extinguishers and first aid kits, and regularly check their effectiveness.
The operator needs to be familiar with the location and usage of the emergency stop button, and immediately stop the machine and report any abnormal situations.

4. Maintenance and upkeep
Daily cleaning
After each use, wipe the surface of the furnace body with a soft cloth to remove dust and oil stains.
Regularly clean the inner wall of the furnace tube to prevent impurities from accumulating and affecting heat transfer efficiency or contaminating materials.
regular inspection
Electrical system: Check the power cords, plugs, and sockets for looseness or aging every month, and replace them if necessary.
Seals: Check the sealing ring quarterly for deformation or cracking, and replace aging parts in a timely manner.
Heating element: Check the heating wire for breakage or oxidation every six months and replace it if necessary.
Gas system: Check gas cylinders, pipelines, and valves for leaks every year, and replace expired gas cylinders.
lubricating maintenance
Regularly add lubricating oil to moving parts such as furnace door hinges and lifting mechanisms to ensure flexible operation.
Avoid lubricating oil contact with high-temperature components to prevent carbonization or combustion.
Calibration and Calibration
Calibrate temperature controllers, pressure gauges, flow meters, and other instruments annually to ensure accurate display.
Optimize PID parameters of the temperature control system to improve temperature control accuracy.

5. Special process precautions
high-temperature annealing
Strictly control the annealing temperature and time to avoid overburning or undercooking that may result in material performance failure.
For easily oxidizable materials, annealing should be carried out under vacuum or inert gas protection.
Chemical Vapor Deposition (CVD) Coating
Accurately control the proportion and flow rate of reaction gases to ensure uniform composition of the film.
Avoid gas pipeline blockage or backflow to prevent explosion risks.
vacuum heat treatment
When the vacuum degree is insufficient, it is strictly prohibited to introduce reaction gas to prevent oxidation or poisoning.
Vacuum pumps require regular maintenance to ensure pumping efficiency.