1、 Pre preparation: Security and Tool Assurance
Safe shutdown: CloseFour ring food freeze dryerConfirm that the temperature of the shelf has returned to room temperature and the vacuum degree has been completely relieved before operating the main power supply, refrigeration, and vacuum system switches to avoid low-temperature frostbite or pressure risks.
Material cleaning: Thoroughly remove the material tray and residual materials from the freeze-drying warehouse, collect scraps and debris, and avoid the spread of pollutants during cleaning.
Complete tools: Prepare nylon soft brushes, lint free cotton cloth, specialized cleaning tanks, food grade disinfectants (such as 200ppm sodium hypochlorite, 75% alcohol), ATP detectors, and vacuum pump oil (factory specified model) and other consumables.
2、 Partition cleaning: point by point processing from outside to inside
（1） External cleaning (after each batch)
Wipe the equipment casing, control panel, and door handle with a dry cotton cloth to remove surface dust; Clean the gaps with a cotton swab dipped in 75% alcohol to prevent oil accumulation.
Clean the surface of the radiator with a vacuum cleaner (with a brush suction head) every month to ensure smooth heat dissipation. If the environment is dusty, increase the frequency.
（2） Internal core area cleaning (after each batch+weekly deep cleaning)
Freeze drying chamber and shelf:
Routine cleaning: Rinse the warehouse walls and shelves with purified water at 60-70 ℃, and clean the gaps with nylon brushes to avoid scratching the stainless steel surface with metal brushes (which can easily breed bacteria).
Deep cleaning: Dismantle shelves and material trays weekly, soak them in a 1% sodium hydroxide solution at 50 ℃ for 2 hours to remove grease residue, and then rinse and dry them with a high-pressure water gun.
Cold trap cleaning:
After the cold trap has defrosted, wipe the frost and accumulated liquid on the inner wall with a cotton cloth. For stubborn stains, use neutral detergent and warm water to wipe, and finally rinse with purified water and air dry.
Multiple manifolds and interfaces:
Disassemble the multi manifold and wipe the interface with a soft cloth dipped in neutral cleaning agent to avoid scratching the sealing surface; Gently wipe the sealing ring with an alcohol cotton ball, check for any damage, and then reset it.
（3） Disinfection and verification (after each cleaning)
Instant food production: Spray the contact surface with 200ppm sodium hypochlorite solution, let it stand for 15 minutes, and then rinse with purified water; Infant and toddler food production can use ultraviolet irradiation for 30 minutes (replaced when the lamp illumination is less than 70 μ W/cm ²).
After disinfection, verify with an ATP detector that the surface microorganisms must be ≤ 10RLU to ensure compliance with food hygiene standards.
3、 Core system maintenance: Key control of vacuum pumps and seals
（1） Vacuum pump maintenance (every 1000 hours or when oil quality is abnormal)
Oil level and quality inspection: Observe the oil level in the window every week (at 1/2-2/3). If the oil color is emulsified, cloudy, or has metal shavings, replace it immediately.
Oil change process:
Open the oil drain plug, use a dedicated container to receive waste oil (for environmental disposal), drain it completely, and tighten the plug;
Inject new oil to the mark, start running for 5 seconds, then stop and drain the oil (flush the oil circuit), repeat once, and finally inject oil.
Performance verification: Monitor the ultimate vacuum value after oil change. If it continues to rise by ≥ 5Pa, check for leaks or pump head faults.
（2） Seal and pipeline inspection (monthly)
Check the sealing ring of the freeze-drying chamber door and the sealing gasket of the cold trap cover for aging and cracks, and replace them as a whole every 6 months; Apply food grade lubricating grease at the interface to enhance sealing.
Apply soapy water to the vacuum pipeline interface, start the vacuum pump and observe for no bubbles to confirm no leaks.
4、 Recovery and recording: Ensure the normal operation of the device
Component reset:Four ring food freeze dryerInstall the shelves, multiple manifolds, and other components in reverse order of disassembly, ensuring that the interfaces are aligned and the seals are compacted to avoid deformation caused by forced assembly.
Trial operation: Connect the power supply, run without load for 30 minutes, check if the vacuum degree and cooling temperature are normal, and if there are no abnormal noises, it can be put into use.
Record and archive: Detailed records of cleaning time, area, disinfectant type, and ATP test results. Vacuum pump maintenance should be marked with operating hours and oil quality status for easy traceability.