The following are the requirements for the use of freeze-drying foundation make-up freeze-drying machine:

1. Power supply and environmental conditions

Independent power socket: An independent power socket must be used to ensure electrical safety and stable operation of the equipment.

Suitable ambient temperature: The working environment temperature should be between 5-30 ℃, which is beneficial for the service life of low-temperature compressors. If it is kept above 30 ℃ for a long time, it may cause damage to the compressor. At the same time, the operating environment temperature should not exceed 28 ℃, and the continuous working time should not exceed 48 hours to avoid equipment overheating affecting performance.

2. Pre freezing treatment of freeze-drying foundation make-up freeze-drying machine

Pre freezing temperature requirement: The material must be fully frozen and compacted, and the pre freezing temperature is generally below -30 ℃; For non water soluble substances (such as organic soluble substances) or samples with high concentrations of sugars above 80% that are not easily frozen, they need to be pre frozen in a pre freezing chamber below -80 ℃ for at least 24 hours, preferably at least 48 hours. In addition, the pre freezing temperature must be 5-10 degrees Celsius below the eutectic point of the material and maintained for a period of time after reaching the target temperature to ensure complete internal freezing of the material.

Sample placement method: Place the material to be freeze-dried evenly on the shelf of the freeze-drying machine to avoid excessive thickness of the material. It is recommended that the liquid sample should not exceed 1cm, and the block sample should be cut thin to improve drying efficiency. Meanwhile, ensure that the sample temperature sensor is securely fixed in place.

3. Vacuum system operation

Pre start inspection: Before using the vacuum pump, it is necessary to check whether the outlet valve is tightened and whether the inflation valve is closed to prevent the pump oil from being sucked back. Also, observe the oil level and quality of the vacuum pump to ensure sufficient oil level and good oil quality.

Vacuum pumping process: When the temperature of the condenser drops below -40 ℃, perform preliminary vacuum pumping first, and then turn on the vacuum pump to further evacuate the condenser. When the vacuum gauge on the control panel displays a certain value, the formal freeze-drying process begins. Under normal circumstances, the system pressure should reach the working vacuum degree within the specified time. If the pressure drops abnormally, it is necessary to check the sealing or vacuum pump status.

Backfilling gas control: When backfilling with N2 or air, please adjust the pressure of the vacuum backfill gas to below 0.7Kg and control the intake speed to avoid damaging the structure of the freeze-dried material due to airflow.

4. Drying process control of freeze-drying foundation make-up freeze-drying machine

Cold trap temperature maintenance: During the sublimation stage, the cold trap temperature must always be at least 20 degrees Celsius lower than the material temperature to ensure sufficient capture of sublimated water vapor.

Parameter setting and adjustment: Reasonably set parameters such as freeze-drying time, temperature, and vacuum degree based on the characteristics of the sample. For example, the temperature during the main drying stage can be set to the freezing point of the sample plus (-10 ℃). For special materials such as cosmetics freeze-dried foundation make-up, specific process data should also be determined according to the formula characteristics, eutectic point, eutectic point, thermal conductivity and other factors, including pre freezing temperature, cooling rate, vacuum degree adjustment value, primary drying temperature range, heating rate, as well as the temperature control range and heating rate, holding time and temperature of analytical drying.

5. Equipment operation specifications

Preparation for startup: Check for any signs of damage or deformation in the main unit, drying chamber, drying rack, and other components of the freeze-drying machine; Use neutral cleaning agents to wipe the interior, shelves, condenser tubes, and other parts to remove impurities and pollutants; Check the pipeline connection to ensure that the vacuum pump is tightly connected to the host and there is no air leakage.

Shutdown operation: Record the temperature and air pressure values before shutdown; Gently press and hold the inflation valve on the control panel, wait for the air pressure to rise, and then turn off the vacuum pump; When the pressure display returns to atmospheric pressure, open the organic glass cover and take out the sample; Turn off the refrigeration unit, main switch, and power switch; After waiting for the ice in the cold trap to melt, open the outlet valve to release water and clean the inner wall of the cold trap with a dry cloth.

Avoid frequent switching: During operation, try to avoid frequent switching of equipment. If the refrigeration unit stops running due to operational errors, wait at least 20 minutes before restarting to avoid damaging the refrigeration unit.

6. Precautions for sample handling of freeze-drying foundation make-up freeze-drying machine

Expanding surface area: Maximizing the surface area of the sample as much as possible can help improve drying efficiency.

Avoid special substances: Try to avoid acidic and alkaline substances as well as volatile organic solvents in the sample to avoid affecting the freeze-drying effect or causing corrosion to the equipment.

Sealed packaging: After freeze-drying, open the valve to ensure consistent indoor and outdoor pressure before removing the material. The removed material should be quickly sealed and packaged to prevent moisture absorption.