Daily Maintenance Of Freeze Dryer
Make sure your freeze dryer is compatible with the eutectic temperature of your sample(s)
First and foremost, ensure your sample is compatible with your freeze dry system before you use the unit. A good rule of thumb is to plan for your most challenging sample and choose a system based on that need.
It's not possible to modify a freeze dryer’s condenser temperature.
The condenser temperature should be 10 to 15°C below the sample’s eutectic point. Low freezing point solvents, for instance, should not be used on -50°C units.
Certain acids should not be used with bare stainless steel and should only be used with PTFE models. Systems that reach -84°C are ideal for lyophilizing samples with low eutectic temperatures (like those that contain acetonitrile).
Systems that reach -105°C can handle samples containing small amounts of ethanol.
Perform regular vacuum pump maintenance
Regular and correct maintenance of the vacuum pump can maintain the performance and service life of the vacuum pump;
first ensure that the material is suitable for the type of lyophilizer.
1. if it is an oil pump, the oil must be replaced regularly, at least 500 hours; if the oil is not clear, dirty or emulsified, it must be replaced immediately.
2. in the freeze-drying process, there are many dust-generated materials, so it is necessary to select the appropriate dust filter to reduce or even avoid dust entering the vacuum pump. if not, the lyophilization process by observing the pump oil mirror to see if the oil is cloudy.
3. some materials need to be lyophilized by adding organic solvents or acid traps between the lyophilizer and the vacuum pump;
general pumps are suitable for water based materials, organic solvents or acidic materials with the choice of molecular hybrid pumps, or other ways to remove organic solvents or acids.
Clean the freeze dryer after each running
It's necessary to defrost and drain the condenser after each standard run.
After each use, there must be no water in the cold trap. Each component containing chemicals or organic solvents should be cleaned. Keep water, especially water containing chemicals, out of the cold trap.
If acid is used, it must be neutralized where the cold trap touches;
Notes for use:
1. Materials not fully pre-frozen shall not be dried; Otherwise, a large amount of water will evaporate or sublimate, so that the cold trap can not catch in time and into the vacuum pump.
2. 2. If the material begins to melt during the freeze-drying process, the material should be removed from the freeze-drying machine in time.
Section of vacuum gauge
The vacuum gauge generally adopts pirani vacuum gauge or thermocouple type vacuum gauge.
Pilani resistance type measurement range is wide and can be measured from 0.5Pa to 110kpa. Generally, tungsten wire with high precision resistance is used to make it. In case of high oxygen direct power supply, it is easy to burn out.
After the use of the lyophilizer, the cold trap is not cleaned in time, which is more likely to damage the vacuum gauge.
The measuring range of thermocouple type vacuum gauge is relatively narrow, generally below 200pa, but the freeze-drying range of lyophilizer is generally between 5-20pa, during which the vacuum measurement can be used, and the thermocouple type is more durable than pirani type.
