1Four ring vacuum freeze dryerPre startup inspection: the foundation for safe startup
Power and Circuit Inspection
Confirm that the power supply voltage, phase number, and frequency are consistent with the equipment nameplate (such as 380V/50Hz), and that the power cord connection is secure and not loose.
Check if the piping connections of the system are securely locked to prevent refrigerant leakage.
Environment and equipment status
The equipment should be placed steadily with an ambient temperature of ≤ 30 ℃ (some models such as LGJ-12C require lower temperatures) to ensure heat dissipation efficiency.
Check if the ball valve at the front end of the automatic drain valve is open to prevent condensation from accumulating.
Refrigeration system pressure
Observe the low-pressure gauge (normal range of 60-85Psig) and high-pressure gauge (120-240Psig) of the refrigerant. If the pressure is abnormal, check the condenser heat dissipation or refrigerant leakage.
2、 Startup and Pre cooling: Establishing Drying Efficiency
Start the device
Press the "ON" button on the control box to start the compressor, and the refrigerant low-pressure gauge pointer should remain stable at 60-85Psig.
If the pressure is below 140Psig, the antifreeze switch triggers the condenser fan to stop running, and the ambient temperature or refrigeration system needs to be checked.
Cold trap pre cooling
Start the refrigeration unit and quickly reduce the temperature of the cold trap to the set value (for example, LGJ-12C can drop from 20 ℃ to -40 ℃ within 20 minutes, with a limit of -65 ℃).
During the pre cooling process, the temperature is monitored through a display screen to ensure that the temperature of the cold trap meets the standard (such as<-62 ℃) before proceeding to the next step.
3、 Material loading and pre freezing: ensuring uniform drying
Material preparation
Evenly spread the pre processed (cleaned, sliced, etc.) materials in a material tray, with a recommended thickness of ≤ 10mm per tray to avoid stacking and affecting sublimation efficiency.
Place the material tray in the freeze-drying rack, and place the temperature sensor in any layer of the material tray to monitor the temperature in real time.
Pre freezing operation
Place the freeze-drying rack into the cold trap, cover with insulation cover, and pre freeze for 4 hours (or until the material center temperature is ≤ -40 ℃) to ensure complete freezing.
After pre freezing is completed, quickly transfer to the drying room to reduce the risk of ice crystal melting.
4、 Vacuum pumping and drying: core process control
Vacuum pumping stage
Close the warehouse door, tighten the drainage and inflation valve, and start the vacuum pump.
The vacuum degree should be reduced from standard atmospheric pressure to ≤ 5Pa within 10 minutes (such as LGJ-12C reaching the standard value). If the decrease is slow, the vacuum pump oil level or system leakage should be checked.
Sublimation drying
After the vacuum degree stabilizes, the heating plate gradually heats up (it is recommended to start at -30 ℃ and raise 5 ℃ every 2 hours) to promote the direct sublimation of ice crystals into water vapor.
Closely monitor the vacuum degree (≤ 10Pa) and cold trap temperature (to prevent ice blockage), and adjust the sublimation time according to the material moisture content (usually 12-24 hours).
Analyze drying
After sublimation is completed, the temperature of the heating plate is raised to 30-40 ℃ to remove residual moisture (such as controlling the temperature to avoid denaturation of protein drugs).
The recommended analysis time is 8-12 hours, and the final vacuum degree can be maintained at ≤ 1Pa.
5、 Shutdown and maintenance: extending equipment lifespan
Shutdown procedure
Turn off the heating plate and vacuum pump, slowly open the intake valve to restore the pressure to normal (to avoid rapid intake causing material backflow).
Remove the material tray, turn off the refrigeration unit, and press the "OFF" button to cut off the power.
Cold trap defrosting
Wait for the cold trap to naturally melt or activate the defrosting program (supported by some models), drain the accumulated water and clean the inner wall of the cold trap to prevent bacterial growth.
routine maintenance
Vacuum pump maintenance: Run the pneumatic valve for 2 hours every week and regularly replace the vacuum pump oil (oil level to 1/2 of the sight glass).
Condenser cleaning: Use compressed air to blow away dust every month to ensure efficient heat dissipation.
Sealing ring inspection: Check whether the sealing ring of the warehouse door is aging every quarter and replace it in a timely manner to maintain the vacuum degree.
VIFour ring vacuum freeze dryerOperational precautions: Avoid common risks
safety protection
Wear goggles and antifreeze gloves during operation to avoid low-temperature frostbite or injury caused by broken glass covers.
Do not touch the cold trap or heating plate during device operation to prevent burns or frostbite.
parameter control
The heating rate of the heating plate should be ≤ 3 ℃/hour to avoid cracking caused by severe shrinkage of the material.
When the vacuum fluctuation exceeds ± 5Pa, the machine should be stopped for inspection to prevent material oxidation or uneven drying.
emergency response
When there is a sudden power outage, immediately turn off the main power and manually evacuate the vacuum chamber to protect the materials.
When the vacuum pump makes abnormal noise or the oil level drops too quickly, immediately stop the machine for maintenance to prevent damage to the pump body.