1. What is the leakage rate of vacuum freeze dryer
The leakage rate refers to the pressure rise of the freeze-dried case in unit time t (the pressure difference between the initial pressure P1 and the end pressure P2). Leakage rate = (p2-p1) * V / T
2. The specific operation process is as follows (take RTFD-GZL5 as an example).
1) Wipe the water inside the drying bin and cold trap to make sure there is no liquid;
2) Wipe the sealing strip to make sure there are no foreign matters. If the sealing strip is aged, please replace the same type of sealing strip;
3) Close the box door and valve, connect the vacuum gauge and the vacuum pump (there must be a stop valve between the vacuum pump and the box);
4) The diaphragm temperature is controlled at + 20 ℃, and the cold trap temperature is kept at the lowest value;
5) Start vacuumizing. When the vacuum value is close to the limit vacuum of the equipment (such as 5pa (0.05mba)), close the stop valve and the vacuum pump. The time T1 and vacuum P1 were recorded;
6) The process of testing and recording is consistent with that of no-load testing, but the fluctuation of diaphragm temperature and cold trap temperature should not be too large;
7) If the actual leakage rate of the calculation equipment is less than or equal to 0.025 PA * m 3 / s or 0.00025mba * m 3 / s, it is qualified.
8) Record the leakage rate L1 of the current equipment, which will change slightly with the service life of the equipment. The detection of vacuum leakage rate should be taken as an index of routine detection of equipment, generally at least once a month;
9) The leakage rate of the final test can be used as the basis for judging the drying end point of the product;
10) When the leakage rate is close to L1, it can be considered that the freeze-drying of the product is finished; when the actual leakage rate is different from L1, it can be considered that the freeze-drying of the product is not finished;
11) The vacuum leakage rate can be used as a basis for judging the end of freeze-drying, which needs to be combined with the process, product temperature and other comprehensive judgment.
