Freeze dryer in the usual daily life much seen, air freeze drying technology, referred to as freeze drying, also known as sublimation air drying. Freeze-drying is a specific method of pre-freezing water-containing materials and subsequently sublimating them under vacuum to obtain air-dried objects. After freeze-drying, the original biological and chemical properties of the objects remain basically unchanged, which is easy to be preserved for a long time, and can be restored to the form before freeze-drying after adding water and soaking, and its original biochemical properties can be maintained. Therefore, freeze-drying technology is widely used in various fields such as industrial chemistry and medical devices. However, many people are not very clear about how to use freeze dryer, freeze dryer for the notes are not very well known, then let's go together to better understand the freeze dryer. Let us first understand the operation of the freeze dryer and prepare for adequate work: freeze dryer in the operation of the preparatory work before
Freeze dryer before use, the first to prepare for the air drying of the object placed in a low-temperature refrigerator or liquid nitrogen, so that the object frozen solid, you can carry out the freeze drying. The host and the vacuum pump are connected with each other by the vacuum pipe, and the standard clamp is used at the connection. The clamp contains a sealing rubber ring, which can be coated with appropriate amount of vacuum grease before connection, and then tightened with the clamp. There is a power socket for the vacuum pump on the right side panel of the main unit, connect the power cord of the vacuum pump. Check the vacuum pump and make sure that it has been filled with vacuum pump oil and cannot run without oil. The oil level should not be less than the center line of the oil mirror. Host cold trap above the "o" type sealing rubber ring should be kept clean, * the first time you use, can be coated with a thin layer of vacuum grease, plexiglass cover placed on the rubber ring, gently rotate a few times, is conducive to sealing.
Operation of freeze dryer
1, boot
2, pre-freezing - the sample tray into the pre-freezing rack and placed in the cold trap, thermometer probe placed on the upper sample tray, cover the sealing lid. Click the "Chiller" switch on the screen to pre-freeze for 3 hours.
3. Replace the drying rack - after the end of the pre-freezing, remove the sample tray from the cold trap, quickly loaded into the drying rack, the drying rack is placed on the top of the cold trap, covered with a plexiglass cover, the drying cover and the lower end of the "O" sealing ring contact.
4, drying - check whether the inflatable valve is tightened, click on the screen "vacuum meter", such as showing the vacuum degree of 110kPa, click on "vacuum pump". The vacuum pump will turn on and run, and the vacuum will drop rapidly to below 20Pa as normal.
5, dryness check - after the time of drying operation, check the sample curve and the visual sense of the sample has been dry, slowly open the inflation valve, so that the pressure inside the freeze dryer back to 110kPa. click on the "vacuum pump", close the vacuum pump. Click "Vacuum Pump" to turn off the vacuum pump. Click "Vacuum Gauge", turn off the vacuum gauge.
6, end of drying - remove the plexiglass cover, remove the sample tray from the drying rack. Click on "Refrigerant" to turn off the compressor.
7. Wrap up - the moisture in the cold trap melts and flows out of the filling valve, take care to receive it.
8, each use is completed, be sure to record the length of use, a total of 300 hours, change the oil.
Freeze dryer notes:
1, do not operate the process of frequent power switch, if due to faulty operation caused by the refrigeration machine stops running, can not be opened immediately, wait less than 20 minutes before you can re-open, to avoid damage to the refrigeration machine.
2, each freeze-drying, cold trap coils on the ice into water, use a hand towel to clean up the end of the dry freeze-drying turn on the "inflatable valve" to the cold trap inflatable, slowly, to avoid washing out the vacuum gauge.
3, the preparation of the sample should try to expand its surface area, which can not contain acids and alkalis and volatile organic solvents;
4, the sample must be frozen into ice, if there is any residual liquid will lead to gasification jet;
5, note that the cold trap is about -65 degrees, can be used as a low-temperature refrigerator, but make sure that you wear insulated gloves to operate to avoid frostbite;
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6, before turning on the vacuum pump, test the water valve is not tightened, the inflatable valve is not closed, plexiglass cover and rubber ring contact surface is not clean and free of dirt, good sealing;
7, usually, the device can not be used continuously for more than forty-eight hours;
8, samples in the freezing process, the temperature is gradually reduced to be able to take out the sample after a period of time to return to the warm ( still in a frozen state). still in a frozen state), continue air drying to shorten the air drying time.