Daily maintenance of experimental multi temperature zone rotary furnace

As a precision experimental equipment, the daily maintenance of the experimental multi temperature zone rotary furnace directly affects the stability of equipment performance, accuracy of experimental results, and service life. The following provides a systematic daily maintenance plan from six aspects: cleaning and maintenance, sealing system inspection, heating system maintenance, transmission system maintenance, electrical system testing, and safety accessory verification, combined with specific operating points and precautions:

1. Cleaning and maintenance: prevent pollution and corrosion
External cleaning of furnace body
Operation points: Use a soft dry cloth to wipe the surface of the furnace body, avoid using cleaning agents containing corrosive solvents (such as acetone), and prevent damage to the surface coating.
Caution: If the furnace body is contaminated with oil, it can be wiped with neutral detergent (such as soapy water), then rinsed with clean water and wiped dry.
Internal cleaning of furnace
Operation points:
After cooling down to ≤ 50 ℃, wear heat-resistant gloves and open the furnace door. Use a soft bristled brush to remove any residues (such as oxides and carbides) inside the furnace.
For stubborn stains, alcohol cotton balls can be used to wipe them, avoiding the use of hard tools to scrape and prevent damage to the inner wall of the furnace (such as alumina ceramic coating).
Attention: When cleaning, turn off the power and hang a “maintenance in progress” warning sign to prevent accidental operation.
Furnace tube cleaning
Operation points:
For quartz furnace tubes, rinse them with deionized water and dry them with nitrogen to avoid residual water stains that may cause them to explode at high temperatures.
For metal furnace tubes (such as stainless steel), they can be soaked in a 10% citric acid solution for 30 minutes, rinsed with deionized water, and dried.
Attention: Before cleaning, it is necessary to confirm the material of the furnace tube and avoid using cleaning agents that react with the material (such as strong acids that corrode stainless steel).

2. Sealing system inspection: Ensure vacuum and atmosphere stability
Sealing ring inspection and replacement
Operation points:
Check the sealing rings of the furnace door, air inlet, and exhaust outlet every week to observe whether there are cracks, deformations, or aging phenomena.
If there are cracks or permanent compression deformation of ≥ 25% on the surface of the sealing ring, it needs to be replaced immediately (such as the service life of fluororubber sealing rings is usually 1-2 years).
Attention: When replacing the sealing ring, special lubricating grease (such as silicon-based grease) should be applied to reduce friction and improve sealing performance.
vacuum test
Operation points:
Conduct a monthly vacuum test, close all intake valves, start the vacuum pump to draw ≤ 10 Pa, and record the pressure increase after holding for 30 minutes.
If the pressure rises by ≥ 5 Pa/min, it is necessary to check whether there are any leakage points in the furnace body (such as welds and flange connections).
Attention: Before testing, it is necessary to confirm that the oil level of the vacuum pump is normal and that the pump body has no abnormal vibration or noise.

3. Heating system maintenance: maintain temperature uniformity and accuracy
Heating element inspection
Operation points:
Check the surface of heating elements (such as silicon molybdenum rods and silicon carbon rods) quarterly for any oxide layer or fracture phenomenon.
If the thickness of the oxide layer is ≥ 0.5 mm, it needs to be gently sanded off with sandpaper (400 grit) to restore the surface smoothness.
Attention: Wear a dust mask when polishing to avoid inhaling silica dust.
Thermocouple calibration
Operation points:
Send thermocouples to the metrology department for calibration every six months to ensure a temperature measurement error of ≤ ± 1 ℃.
Before calibration, it is necessary to check whether the thermocouple protective sleeve is damaged. If it is damaged, it needs to be replaced (such as the corundum sleeve with a temperature resistance of ≤ 1600 ℃).
Attention: After calibration, the temperature controller parameters need to be recalibrated to avoid temperature display deviation.

4. Maintenance of transmission system: ensuring rotational stability
Lubrication of gearbox
Operation points:
Check the oil level of the gearbox every 3 months. If the oil level is below the lower limit of the oil standard, it is necessary to replenish industrial gear oil (such as ISO VG 320).
Replace the lubricating oil once a year and clean the oil tank to prevent impurities from wearing down the gears.
Attention: When replacing lubricating oil, the machine should be stopped and the power should be cut off to avoid the risk of electric shock.
Inspection of supporting wheels and rolling rings
Operation points:
Check the surface of the idler and rolling ring for wear or offset every month. If the wear depth is ≥ 1 mm, adjust the position of the idler or replace it.
Use a spirit level to check the levelness of the furnace body, ensuring a deviation of ≤ 0.1 mm/m to prevent vibration during rotation.
Attention: When adjusting the supporting wheel, special tools should be used to avoid excessive force that may cause deformation of the furnace body.

5. Electrical system testing: prevention of short circuit and leakage
Tightening of wiring terminals
Operation points:
Check all wiring terminals (such as power cords, thermocouple wires, heating element wires) quarterly for looseness or oxidation.
If oxidation is found, use sandpaper (600 grit) to polish the contact surface and re tighten the terminals.
Attention: When tightening, use a torque wrench to avoid damaging the terminals with excessive force.
Insulation resistance test
Operation points:
Every year, use a megohmmeter (500 V range) to test the insulation resistance between the furnace body and the ground wire, ensuring it is ≥ 1 M Ω.
If the insulation resistance is less than 0.5 M Ω, it is necessary to check whether the insulation layer of the heating element or motor is damaged and repair it in a timely manner.
Attention: Before testing, all power sources must be disconnected and a “Do Not Close” warning sign must be hung.

6. Security Attachment Verification: Ensuring the Safe Operation of Equipment
Test of over temperature protection device
Operation points:
Simulate overheating scenarios every six months (such as manually triggering temperature controller faults), and test whether the overheating protection device can cut off power within ≤ 5 seconds.
If the protective device fails, the temperature control module or relay should be replaced immediately.
Attention: During testing, a temperature sensor should be placed inside the furnace to monitor temperature changes in real time.
Gas leakage detection
Operation points:
Check the gas pipeline (such as hydrogen and nitrogen) connections for leaks with soapy water every month. If bubbles are found, tighten the joints or replace the sealing gasket.
For hydrogen pipelines, hydrogen alarm devices should be equipped and regularly calibrated (sensitivity ≤ 10 ppm).
Attention: During testing, all gas sources must be turned off and a “No Ventilation” warning sign must be hung.